1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
|
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8"/>
<meta content="width=device-width, initial-scale=1.0" name="viewport"/><meta content="Docutils 0.17.1: http://docutils.sourceforge.net/" name="generator"/>
<title>Improve performance of pyo programs — Pyo 1.0.5 documentation</title>
<link href="_static/pygments.css" rel="stylesheet" type="text/css"/>
<link href="_static/agogo.css" rel="stylesheet" type="text/css"/>
<link href="_static/sphinx-codeautolink.css" rel="stylesheet" type="text/css"/>
<link href="_static/autoclasstoc.css" rel="stylesheet" type="text/css"/>
<script data-url_root="./" id="documentation_options" src="_static/documentation_options.js"></script>
<script src="_static/jquery.js"></script>
<script src="_static/underscore.js"></script>
<script src="_static/_sphinx_javascript_frameworks_compat.js"></script>
<script src="_static/doctools.js"></script>
<script src="_static/sphinx_highlight.js"></script>
<link href="_static/E-PyoIcon.ico" rel="shortcut icon"/>
<link href="about.html" rel="author" title="About these documents"/>
<link href="genindex.html" rel="index" title="Index"/>
<link href="search.html" rel="search" title="Search"/>
<link href="api/index.html" rel="next" title="API documentation"/>
<link href="winaudioinspect.html" rel="prev" title="Configuring the audio output (Windows)"/>
</head><body>
<div class="header-wrapper" role="banner">
<div class="header">
<div class="headertitle"><a href="index.html">Pyo 1.0.5 documentation</a></div>
<div aria-label="related navigation" class="rel" role="navigation">
<a accesskey="P" href="winaudioinspect.html" title="Configuring the audio output (Windows)">previous</a> |
<a accesskey="N" href="api/index.html" title="API documentation">next</a> |
<a accesskey="I" href="genindex.html" title="General Index">index</a>
</div>
</div>
</div>
<div class="content-wrapper">
<div class="content">
<div class="sidebar">
<h3>Table of Contents</h3>
<ul class="current">
<li class="toctree-l1"><a class="reference internal" href="about.html">About pyo</a></li>
<li class="toctree-l1"><a class="reference internal" href="download.html">Installing pyo with pip</a></li>
<li class="toctree-l1"><a class="reference internal" href="compiling.html">Compiling pyo from sources</a></li>
<li class="toctree-l1"><a class="reference internal" href="structure.html">Structure of the library</a></li>
<li class="toctree-l1"><a class="reference internal" href="gettingstarted.html">Getting started</a></li>
<li class="toctree-l1"><a class="reference internal" href="winaudioinspect.html">Configuring the audio output (Windows)</a></li>
<li class="toctree-l1 current"><a class="current reference internal" href="#">Improve performance of pyo programs</a></li>
</ul>
<ul>
<li class="toctree-l1"><a class="reference internal" href="api/index.html">API documentation</a></li>
<li class="toctree-l1"><a class="reference internal" href="examples/index.html">Examples</a></li>
<li class="toctree-l1"><a class="reference internal" href="tutorials/index.html">Advanced tutorials</a></li>
</ul>
<div role="search">
<h3 style="margin-top: 1.5em;">Search</h3>
<form action="search.html" class="search" method="get">
<input name="q" type="text"/>
<input type="submit" value="Go"/>
</form>
</div>
</div>
<div class="document">
<div class="documentwrapper">
<div class="bodywrapper">
<div class="body" role="main">
<section id="improve-performance-of-pyo-programs">
<h1>Improve performance of pyo programs<a class="headerlink" href="#improve-performance-of-pyo-programs" title="Permalink to this heading">¶</a></h1>
<p>This document lists various tips that help to improve the performance of your
pyo programs.</p>
<section id="python-tips">
<h2>Python tips<a class="headerlink" href="#python-tips" title="Permalink to this heading">¶</a></h2>
<p>There is not much you can do at the Python level because once the script has
finished its execution run, almost all computations are done in the C level
of pyo. Nevertheless, there is these two tricks to consider:</p>
<section id="adjust-the-interpreter-s-check-interval">
<h3>Adjust the interpreter’s “check interval”<a class="headerlink" href="#adjust-the-interpreter-s-check-interval" title="Permalink to this heading">¶</a></h3>
<p>You can change how often the interpreter checks for periodic things with
<cite>sys.setcheckinterval(interval)</cite>. The defaults is 100, which means the check
is performed every 100 Python virtual instructions. Setting it to a larger
value may increase performance for programs using threads.</p>
</section>
<section id="use-the-subprocess-or-multiprocessing-modules">
<h3>Use the subprocess or multiprocessing modules<a class="headerlink" href="#use-the-subprocess-or-multiprocessing-modules" title="Permalink to this heading">¶</a></h3>
<p>You can use the subprocess or multiprocessing modules to spawn your processes
on multiple processors. From the python docs:</p>
<blockquote>
<div><p>The multiprocessing package offers both local and remote concurrency,
effectively side-stepping the Global Interpreter Lock by using subprocesses
instead of threads. Due to this, the multiprocessing module allows the
programmer to fully leverage multiple processors on a given machine.
It runs on both Unix and Windows.</p>
</div></blockquote>
<p>Here is a little example of using the multiprocessing module to spawn a lot of
sine wave computations to multiple processors.</p>
<div class="highlight-python notranslate"><div class="highlight"><pre><span></span><span class="ch">#!/usr/bin/env python</span>
<span class="c1"># encoding: utf-8</span>
<span class="sd">"""</span>
<span class="sd">Spawning lot of sine waves to multiple processes.</span>
<span class="sd">From the command line, run the script with -i flag.</span>
<span class="sd">Call quit() to stop the workers and quit the program.</span>
<span class="sd">"""</span>
<span class="kn">import</span> <span class="nn">time</span>
<span class="kn">import</span> <span class="nn">multiprocessing</span>
<span class="kn">from</span> <span class="nn">random</span> <span class="kn">import</span> <span class="n">uniform</span>
<span class="kn">from</span> <a class="sphinx-codeautolink-a" href="api/alphabetical.html#module-pyo" title="pyo"><span class="nn">pyo</span></a> <span class="kn">import</span> <a class="sphinx-codeautolink-a" href="api/classes/server.html#pyo.Server" title="pyo.lib.server.Server"><span class="n">Server</span></a><span class="p">,</span> <a class="sphinx-codeautolink-a" href="api/classes/generators.html#pyo.SineLoop" title="pyo.lib.generators.SineLoop"><span class="n">SineLoop</span></a>
<span class="k">class</span> <span class="nc">Group</span><span class="p">(</span><span class="n">multiprocessing</span><span class="o">.</span><span class="n">Process</span><span class="p">):</span>
<span class="k">def</span> <span class="fm">__init__</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">num_of_sines</span><span class="p">):</span>
<span class="nb">super</span><span class="p">(</span><span class="n">Group</span><span class="p">,</span> <span class="bp">self</span><span class="p">)</span><span class="o">.</span><span class="fm">__init__</span><span class="p">()</span>
<span class="bp">self</span><span class="o">.</span><span class="n">daemon</span> <span class="o">=</span> <span class="kc">True</span>
<span class="bp">self</span><span class="o">.</span><span class="n">_terminated</span> <span class="o">=</span> <span class="kc">False</span>
<span class="bp">self</span><span class="o">.</span><span class="n">num_of_sines</span> <span class="o">=</span> <span class="n">num_of_sines</span>
<span class="k">def</span> <span class="nf">run</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span>
<span class="c1"># All code that should run on a separated</span>
<span class="c1"># core must be created in the run() method.</span>
<span class="bp">self</span><span class="o">.</span><span class="n">server</span> <span class="o">=</span> <a class="sphinx-codeautolink-a" href="api/classes/server.html#pyo.Server" title="pyo.lib.server.Server"><span class="n">Server</span></a><span class="p">()</span>
<span class="bp">self</span><span class="o">.</span><span class="n">server</span><span class="o">.</span><span class="n">deactivateMidi</span><span class="p">()</span>
<span class="bp">self</span><span class="o">.</span><span class="n">server</span><span class="o">.</span><span class="n">boot</span><span class="p">()</span><span class="o">.</span><span class="n">start</span><span class="p">()</span>
<span class="n">freqs</span> <span class="o">=</span> <span class="p">[</span><span class="n">uniform</span><span class="p">(</span><span class="mi">400</span><span class="p">,</span><span class="mi">800</span><span class="p">)</span> <span class="k">for</span> <span class="n">i</span> <span class="ow">in</span> <span class="nb">range</span><span class="p">(</span><span class="bp">self</span><span class="o">.</span><span class="n">num_of_sines</span><span class="p">)]</span>
<span class="bp">self</span><span class="o">.</span><span class="n">oscs</span> <span class="o">=</span> <a class="sphinx-codeautolink-a" href="api/classes/generators.html#pyo.SineLoop" title="pyo.lib.generators.SineLoop"><span class="n">SineLoop</span></a><span class="p">(</span><span class="n">freq</span><span class="o">=</span><span class="n">freqs</span><span class="p">,</span> <span class="n">feedback</span><span class="o">=</span><span class="mf">0.1</span><span class="p">,</span> <span class="n">mul</span><span class="o">=</span><span class="mf">.005</span><span class="p">)</span><span class="o">.</span><span class="n">out</span><span class="p">()</span>
<span class="c1"># Keeps the process alive...</span>
<span class="k">while</span> <span class="ow">not</span> <span class="bp">self</span><span class="o">.</span><span class="n">_terminated</span><span class="p">:</span>
<span class="n">time</span><span class="o">.</span><span class="n">sleep</span><span class="p">(</span><span class="mf">0.001</span><span class="p">)</span>
<span class="bp">self</span><span class="o">.</span><span class="n">server</span><span class="o">.</span><span class="n">stop</span><span class="p">()</span>
<span class="k">def</span> <span class="nf">stop</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span>
<span class="bp">self</span><span class="o">.</span><span class="n">_terminated</span> <span class="o">=</span> <span class="kc">True</span>
<span class="k">if</span> <span class="vm">__name__</span> <span class="o">==</span> <span class="s1">'__main__'</span><span class="p">:</span>
<span class="c1"># Starts four processes playing 500 oscillators each.</span>
<span class="n">jobs</span> <span class="o">=</span> <span class="p">[</span><span class="n">Group</span><span class="p">(</span><span class="mi">500</span><span class="p">)</span> <span class="k">for</span> <span class="n">i</span> <span class="ow">in</span> <span class="nb">range</span><span class="p">(</span><span class="mi">4</span><span class="p">)]</span>
<span class="p">[</span><span class="n">job</span><span class="o">.</span><span class="n">start</span><span class="p">()</span> <span class="k">for</span> <span class="n">job</span> <span class="ow">in</span> <span class="n">jobs</span><span class="p">]</span>
<span class="k">def</span> <span class="nf">quit</span><span class="p">():</span>
<span class="s2">"Stops the workers and quit the program."</span>
<span class="p">[</span><span class="n">job</span><span class="o">.</span><span class="n">stop</span><span class="p">()</span> <span class="k">for</span> <span class="n">job</span> <span class="ow">in</span> <span class="n">jobs</span><span class="p">]</span>
<span class="n">exit</span><span class="p">()</span>
</pre></div>
</div>
</section>
<section id="avoid-memory-allocation-after-initialization">
<h3>Avoid memory allocation after initialization<a class="headerlink" href="#avoid-memory-allocation-after-initialization" title="Permalink to this heading">¶</a></h3>
<p>Dynamic memory allocation (malloc/calloc/realloc) tends to be
nondeterministic; the time taken to allocate memory may not be predictable,
making it inappropriate for real time systems. To be sure that the audio
callback will run smoothly all the time, it is better to create all audio
objects at the program’s initialization and call their <cite>stop()</cite>, <cite>play()</cite>,
<cite>out()</cite> methods when needed.</p>
<p>Be aware that a simple arithmetic operation involving an audio object will
create a <cite>Dummy</cite> object (to hold the modified signal), thus will allocate
memory for its audio stream AND add a processing task on the CPU. Run this
simple example and watch the process’s CPU growing:</p>
<div class="highlight-python notranslate"><div class="highlight"><pre><span></span><span class="kn">from</span> <a class="sphinx-codeautolink-a" href="api/alphabetical.html#module-pyo" title="pyo"><span class="nn">pyo</span></a> <span class="kn">import</span> <span class="o">*</span>
<span class="kn">import</span> <span class="nn">random</span>
<span class="n">s</span> <span class="o">=</span> <a class="sphinx-codeautolink-a" href="api/classes/server.html#pyo.Server" title="pyo.lib.server.Server"><span class="n">Server</span></a><span class="p">()</span><span class="o">.</span><span class="n">boot</span><span class="p">()</span>
<a class="sphinx-codeautolink-a" href="api/classes/controls.html#pyo.Fader" title="pyo.lib.controls.Fader"><span class="n">env</span></a> <span class="o">=</span> <a class="sphinx-codeautolink-a" href="api/classes/controls.html#pyo.Fader" title="pyo.lib.controls.Fader"><span class="n">Fader</span></a><span class="p">(</span><span class="mf">0.005</span><span class="p">,</span> <span class="mf">0.09</span><span class="p">,</span> <span class="mf">0.1</span><span class="p">,</span> <span class="n">mul</span><span class="o">=</span><span class="mf">0.2</span><span class="p">)</span>
<a class="sphinx-codeautolink-a" href="api/classes/randoms.html#pyo.Randi" title="pyo.lib.randoms.Randi"><span class="n">jit</span></a> <span class="o">=</span> <a class="sphinx-codeautolink-a" href="api/classes/randoms.html#pyo.Randi" title="pyo.lib.randoms.Randi"><span class="n">Randi</span></a><span class="p">(</span><span class="nb">min</span><span class="o">=</span><span class="mf">1.0</span><span class="p">,</span> <span class="nb">max</span><span class="o">=</span><span class="mf">1.02</span><span class="p">,</span> <span class="n">freq</span><span class="o">=</span><span class="mi">3</span><span class="p">)</span>
<span class="n">sig</span> <span class="o">=</span> <a class="sphinx-codeautolink-a" href="api/classes/generators.html#pyo.RCOsc" title="pyo.lib.generators.RCOsc"><span class="n">RCOsc</span></a><span class="p">(</span><span class="n">freq</span><span class="o">=</span><span class="p">[</span><span class="mi">100</span><span class="p">,</span><span class="mi">100</span><span class="p">],</span> <span class="n">mul</span><span class="o">=</span><a class="sphinx-codeautolink-a" href="api/classes/controls.html#pyo.Fader" title="pyo.lib.controls.Fader"><span class="n">env</span></a><span class="p">)</span><span class="o">.</span><span class="n">out</span><span class="p">()</span>
<span class="k">def</span> <span class="nf">change</span><span class="p">():</span>
<span class="n">freq</span> <span class="o">=</span> <a class="sphinx-codeautolink-a" href="api/functions/conv.html#pyo.midiToHz" title="pyo.midiToHz"><span class="n">midiToHz</span></a><span class="p">(</span><span class="n">random</span><span class="o">.</span><span class="n">randrange</span><span class="p">(</span><span class="mi">60</span><span class="p">,</span> <span class="mi">72</span><span class="p">,</span> <span class="mi">2</span><span class="p">))</span>
<span class="c1"># Because `jit` is a PyoObject, both `freq+jit` and `freq-jit` will</span>
<span class="c1"># create a `Dummy` object, for which a reference will be created and</span>
<span class="c1"># saved in the `sig` object. The result is both memory and CPU</span>
<span class="c1"># increase until something bad happens!</span>
<span class="n">sig</span><span class="o">.</span><span class="n">freq</span> <span class="o">=</span> <span class="p">[</span><span class="n">freq</span><span class="o">+</span><a class="sphinx-codeautolink-a" href="api/classes/randoms.html#pyo.Randi" title="pyo.lib.randoms.Randi"><span class="n">jit</span></a><span class="p">,</span> <span class="n">freq</span><span class="o">-</span><a class="sphinx-codeautolink-a" href="api/classes/randoms.html#pyo.Randi" title="pyo.lib.randoms.Randi"><span class="n">jit</span></a><span class="p">]</span>
<span class="n">env</span><span class="o">.</span><span class="n">play</span><span class="p">()</span>
<span class="n">pat</span> <span class="o">=</span> <a class="sphinx-codeautolink-a" href="api/classes/pattern.html#pyo.Pattern" title="pyo.lib.pattern.Pattern"><span class="n">Pattern</span></a><span class="p">(</span><span class="n">change</span><span class="p">,</span> <span class="n">time</span><span class="o">=</span><span class="mf">0.125</span><span class="p">)</span><span class="o">.</span><span class="n">play</span><span class="p">()</span>
<span class="n">s</span><span class="o">.</span><span class="n">gui</span><span class="p">(</span><span class="nb">locals</span><span class="p">())</span>
</pre></div>
</div>
<p>An efficient version of this program should look like this:</p>
<div class="highlight-python notranslate"><div class="highlight"><pre><span></span><span class="kn">from</span> <a class="sphinx-codeautolink-a" href="api/alphabetical.html#module-pyo" title="pyo"><span class="nn">pyo</span></a> <span class="kn">import</span> <span class="o">*</span>
<span class="kn">import</span> <span class="nn">random</span>
<span class="n">s</span> <span class="o">=</span> <a class="sphinx-codeautolink-a" href="api/classes/server.html#pyo.Server" title="pyo.lib.server.Server"><span class="n">Server</span></a><span class="p">()</span><span class="o">.</span><span class="n">boot</span><span class="p">()</span>
<a class="sphinx-codeautolink-a" href="api/classes/controls.html#pyo.Fader" title="pyo.lib.controls.Fader"><span class="n">env</span></a> <span class="o">=</span> <a class="sphinx-codeautolink-a" href="api/classes/controls.html#pyo.Fader" title="pyo.lib.controls.Fader"><span class="n">Fader</span></a><span class="p">(</span><span class="mf">0.005</span><span class="p">,</span> <span class="mf">0.09</span><span class="p">,</span> <span class="mf">0.1</span><span class="p">,</span> <span class="n">mul</span><span class="o">=</span><span class="mf">0.2</span><span class="p">)</span>
<a class="sphinx-codeautolink-a" href="api/classes/randoms.html#pyo.Randi" title="pyo.lib.randoms.Randi"><span class="n">jit</span></a> <span class="o">=</span> <a class="sphinx-codeautolink-a" href="api/classes/randoms.html#pyo.Randi" title="pyo.lib.randoms.Randi"><span class="n">Randi</span></a><span class="p">(</span><span class="nb">min</span><span class="o">=</span><span class="mf">1.0</span><span class="p">,</span> <span class="nb">max</span><span class="o">=</span><span class="mf">1.02</span><span class="p">,</span> <span class="n">freq</span><span class="o">=</span><span class="mi">3</span><span class="p">)</span>
<span class="c1"># Create a `Sig` object to hold the frequency value.</span>
<a class="sphinx-codeautolink-a" href="api/classes/controls.html#pyo.Sig" title="pyo.lib._core.Sig"><span class="n">frq</span></a> <span class="o">=</span> <a class="sphinx-codeautolink-a" href="api/classes/controls.html#pyo.Sig" title="pyo.lib._core.Sig"><span class="n">Sig</span></a><span class="p">(</span><span class="mi">100</span><span class="p">)</span>
<span class="c1"># Create the `Dummy` objects only once at initialization.</span>
<span class="n">sig</span> <span class="o">=</span> <a class="sphinx-codeautolink-a" href="api/classes/generators.html#pyo.RCOsc" title="pyo.lib.generators.RCOsc"><span class="n">RCOsc</span></a><span class="p">(</span><span class="n">freq</span><span class="o">=</span><span class="p">[</span><a class="sphinx-codeautolink-a" href="api/classes/controls.html#pyo.Sig" title="pyo.lib._core.Sig"><span class="n">frq</span></a><span class="o">+</span><a class="sphinx-codeautolink-a" href="api/classes/randoms.html#pyo.Randi" title="pyo.lib.randoms.Randi"><span class="n">jit</span></a><span class="p">,</span> <a class="sphinx-codeautolink-a" href="api/classes/controls.html#pyo.Sig" title="pyo.lib._core.Sig"><span class="n">frq</span></a><span class="o">-</span><a class="sphinx-codeautolink-a" href="api/classes/randoms.html#pyo.Randi" title="pyo.lib.randoms.Randi"><span class="n">jit</span></a><span class="p">],</span> <span class="n">mul</span><span class="o">=</span><a class="sphinx-codeautolink-a" href="api/classes/controls.html#pyo.Fader" title="pyo.lib.controls.Fader"><span class="n">env</span></a><span class="p">)</span><span class="o">.</span><span class="n">out</span><span class="p">()</span>
<span class="k">def</span> <span class="nf">change</span><span class="p">():</span>
<span class="n">freq</span> <span class="o">=</span> <a class="sphinx-codeautolink-a" href="api/functions/conv.html#pyo.midiToHz" title="pyo.midiToHz"><span class="n">midiToHz</span></a><span class="p">(</span><span class="n">random</span><span class="o">.</span><span class="n">randrange</span><span class="p">(</span><span class="mi">60</span><span class="p">,</span> <span class="mi">72</span><span class="p">,</span> <span class="mi">2</span><span class="p">))</span>
<span class="c1"># Only change the `value` attribute of the Sig object.</span>
<span class="n">frq</span><span class="o">.</span><span class="n">value</span> <span class="o">=</span> <span class="n">freq</span>
<span class="n">env</span><span class="o">.</span><span class="n">play</span><span class="p">()</span>
<span class="n">pat</span> <span class="o">=</span> <a class="sphinx-codeautolink-a" href="api/classes/pattern.html#pyo.Pattern" title="pyo.lib.pattern.Pattern"><span class="n">Pattern</span></a><span class="p">(</span><span class="n">change</span><span class="p">,</span> <span class="n">time</span><span class="o">=</span><span class="mf">0.125</span><span class="p">)</span><span class="o">.</span><span class="n">play</span><span class="p">()</span>
<span class="n">s</span><span class="o">.</span><span class="n">gui</span><span class="p">(</span><span class="nb">locals</span><span class="p">())</span>
</pre></div>
</div>
</section>
<section id="don-t-do-anything-that-can-trigger-the-garbage-collector">
<h3>Don’t do anything that can trigger the garbage collector<a class="headerlink" href="#don-t-do-anything-that-can-trigger-the-garbage-collector" title="Permalink to this heading">¶</a></h3>
<p>The garbage collector of python is another nondeterministic process. You
should avoid doing anything that can trigger it. So, instead of deleting
an audio object, which can turn out to delete many stream objects, you
should just call its <cite>stop()</cite> method to remove it from the server’s
processing loop.</p>
</section>
</section>
<section id="pyo-tips">
<h2>Pyo tips<a class="headerlink" href="#pyo-tips" title="Permalink to this heading">¶</a></h2>
<p>Here is a list of tips specific to pyo that you should consider when trying to
reduce the CPU consumption of your audio program.</p>
<section id="mix-down-before-applying-effects">
<h3>Mix down before applying effects<a class="headerlink" href="#mix-down-before-applying-effects" title="Permalink to this heading">¶</a></h3>
<p>It is very easy to over-saturate the CPU with pyo, especially if you use the
multi-channel expansion feature. If your final output uses less channels than
the number of audio streams in an object, don’t forget to mix it down (call
its <cite>mix()</cite> method) before applying effects on the sum of the signals.</p>
<p>Consider the following snippet, which create a chorus of 50 oscillators and
apply a phasing effect on the resulting sound:</p>
<div class="highlight-python notranslate"><div class="highlight"><pre><span></span><a class="sphinx-codeautolink-a" href="api/classes/generators.html#pyo.SineLoop" title="pyo.lib.generators.SineLoop"><span class="n">src</span></a> <span class="o">=</span> <a class="sphinx-codeautolink-a" href="api/classes/generators.html#pyo.SineLoop" title="pyo.lib.generators.SineLoop"><span class="n">SineLoop</span></a><span class="p">(</span><span class="n">freq</span><span class="o">=</span><span class="p">[</span><span class="n">random</span><span class="o">.</span><span class="n">uniform</span><span class="p">(</span><span class="mi">190</span><span class="p">,</span><span class="mi">210</span><span class="p">)</span> <span class="k">for</span> <span class="n">i</span> <span class="ow">in</span> <span class="nb">range</span><span class="p">(</span><span class="mi">50</span><span class="p">)],</span>
<span class="n">feedback</span><span class="o">=</span><span class="mf">0.1</span><span class="p">,</span> <span class="n">mul</span><span class="o">=</span><span class="mf">0.01</span><span class="p">)</span>
<span class="n">lfo</span> <span class="o">=</span> <a class="sphinx-codeautolink-a" href="api/classes/generators.html#pyo.Sine" title="pyo.lib.generators.Sine"><span class="n">Sine</span></a><span class="p">(</span><span class="mf">.25</span><span class="p">)</span><span class="o">.</span><span class="n">range</span><span class="p">(</span><span class="mi">200</span><span class="p">,</span> <span class="mi">400</span><span class="p">)</span>
<span class="n">phs</span> <span class="o">=</span> <a class="sphinx-codeautolink-a" href="api/classes/filters.html#pyo.Phaser" title="pyo.lib.filters.Phaser"><span class="n">Phaser</span></a><span class="p">(</span><a class="sphinx-codeautolink-a" href="api/classes/generators.html#pyo.SineLoop" title="pyo.lib.generators.SineLoop"><span class="n">src</span></a><span class="p">,</span> <span class="n">freq</span><span class="o">=</span><span class="n">lfo</span><span class="p">,</span> <span class="n">q</span><span class="o">=</span><span class="mi">20</span><span class="p">,</span> <span class="n">feedback</span><span class="o">=</span><span class="mf">0.95</span><span class="p">)</span><span class="o">.</span><span class="n">out</span><span class="p">()</span>
</pre></div>
</div>
<p>This version uses around 47% of the CPU on my Thinkpad T430, i5 3320M @ 2.6GHz.
The problem is that the 50 oscillators given in input of the Phaser object
creates 50 identical Phaser objects, one for each oscillator. That is a big
waste of CPU. The next version mixes the oscillators into a stereo stream
before applying the effect and the CPU consumption drops to ~7% !</p>
<div class="highlight-python notranslate"><div class="highlight"><pre><span></span><a class="sphinx-codeautolink-a" href="api/classes/generators.html#pyo.SineLoop" title="pyo.lib.generators.SineLoop"><span class="n">src</span></a> <span class="o">=</span> <a class="sphinx-codeautolink-a" href="api/classes/generators.html#pyo.SineLoop" title="pyo.lib.generators.SineLoop"><span class="n">SineLoop</span></a><span class="p">(</span><span class="n">freq</span><span class="o">=</span><span class="p">[</span><span class="n">random</span><span class="o">.</span><span class="n">uniform</span><span class="p">(</span><span class="mi">190</span><span class="p">,</span><span class="mi">210</span><span class="p">)</span> <span class="k">for</span> <span class="n">i</span> <span class="ow">in</span> <span class="nb">range</span><span class="p">(</span><span class="mi">50</span><span class="p">)],</span>
<span class="n">feedback</span><span class="o">=</span><span class="mf">0.1</span><span class="p">,</span> <span class="n">mul</span><span class="o">=</span><span class="mf">0.01</span><span class="p">)</span>
<span class="n">lfo</span> <span class="o">=</span> <a class="sphinx-codeautolink-a" href="api/classes/generators.html#pyo.Sine" title="pyo.lib.generators.Sine"><span class="n">Sine</span></a><span class="p">(</span><span class="mf">.25</span><span class="p">)</span><span class="o">.</span><span class="n">range</span><span class="p">(</span><span class="mi">200</span><span class="p">,</span> <span class="mi">400</span><span class="p">)</span>
<span class="n">phs</span> <span class="o">=</span> <a class="sphinx-codeautolink-a" href="api/classes/filters.html#pyo.Phaser" title="pyo.lib.filters.Phaser"><span class="n">Phaser</span></a><span class="p">(</span><span class="n">src</span><span class="o">.</span><span class="n">mix</span><span class="p">(</span><span class="mi">2</span><span class="p">),</span> <span class="n">freq</span><span class="o">=</span><span class="n">lfo</span><span class="p">,</span> <span class="n">q</span><span class="o">=</span><span class="mi">20</span><span class="p">,</span> <span class="n">feedback</span><span class="o">=</span><span class="mf">0.95</span><span class="p">)</span><span class="o">.</span><span class="n">out</span><span class="p">()</span>
</pre></div>
</div>
<p>When costly effects are involved, this can have a very drastic impact on the
CPU usage.</p>
</section>
<section id="stop-your-unused-audio-objects">
<h3>Stop your unused audio objects<a class="headerlink" href="#stop-your-unused-audio-objects" title="Permalink to this heading">¶</a></h3>
<p>Whenever you don’t use an audio object (but you want to keep it for future
uses), call its <cite>stop()</cite> method. This will inform the server to remove it from
the computation loop. Setting the volume to 0 does not save CPU (everything is
computed then multiplied by 0), the <cite>stop()</cite> method does. My own synth classes
often looks like something like this:</p>
<div class="highlight-python notranslate"><div class="highlight"><pre><span></span><span class="k">class</span> <span class="nc">Glitchy</span><span class="p">:</span>
<span class="k">def</span> <span class="fm">__init__</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span>
<span class="bp">self</span><span class="o">.</span><span class="n">feed</span> <span class="o">=</span> <a class="sphinx-codeautolink-a" href="api/classes/generators.html#pyo.Lorenz" title="pyo.lib.generators.Lorenz"><span class="n">Lorenz</span></a><span class="p">(</span><span class="mf">0.002</span><span class="p">,</span> <span class="mf">0.8</span><span class="p">,</span> <span class="kc">True</span><span class="p">,</span> <span class="mf">0.49</span><span class="p">,</span> <span class="mf">0.5</span><span class="p">)</span>
<span class="bp">self</span><span class="o">.</span><span class="n">amp</span> <span class="o">=</span> <a class="sphinx-codeautolink-a" href="api/classes/generators.html#pyo.Sine" title="pyo.lib.generators.Sine"><span class="n">Sine</span></a><span class="p">(</span><span class="mf">0.2</span><span class="p">)</span><span class="o">.</span><span class="n">range</span><span class="p">(</span><span class="mf">0.01</span><span class="p">,</span> <span class="mf">0.3</span><span class="p">)</span>
<span class="bp">self</span><span class="o">.</span><span class="n">src</span> <span class="o">=</span> <a class="sphinx-codeautolink-a" href="api/classes/generators.html#pyo.SineLoop" title="pyo.lib.generators.SineLoop"><span class="n">SineLoop</span></a><span class="p">(</span><span class="mi">1</span><span class="p">,</span> <span class="bp">self</span><span class="o">.</span><span class="n">feed</span><span class="p">,</span> <span class="n">mul</span><span class="o">=</span><span class="bp">self</span><span class="o">.</span><span class="n">amp</span><span class="p">)</span>
<span class="bp">self</span><span class="o">.</span><span class="n">filt</span> <span class="o">=</span> <a class="sphinx-codeautolink-a" href="api/classes/filters.html#pyo.ButLP" title="pyo.lib.filters.ButLP"><span class="n">ButLP</span></a><span class="p">(</span><span class="bp">self</span><span class="o">.</span><span class="n">src</span><span class="p">,</span> <span class="mi">10000</span><span class="p">)</span>
<span class="k">def</span> <span class="nf">play</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">chnl</span><span class="o">=</span><span class="mi">0</span><span class="p">):</span>
<span class="bp">self</span><span class="o">.</span><span class="n">feed</span><span class="o">.</span><span class="n">play</span><span class="p">()</span>
<span class="bp">self</span><span class="o">.</span><span class="n">amp</span><span class="o">.</span><span class="n">play</span><span class="p">()</span>
<span class="bp">self</span><span class="o">.</span><span class="n">src</span><span class="o">.</span><span class="n">play</span><span class="p">()</span>
<span class="bp">self</span><span class="o">.</span><span class="n">filt</span><span class="o">.</span><span class="n">out</span><span class="p">(</span><span class="n">chnl</span><span class="p">)</span>
<span class="k">return</span> <span class="bp">self</span>
<span class="k">def</span> <span class="nf">stop</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span>
<span class="bp">self</span><span class="o">.</span><span class="n">feed</span><span class="o">.</span><span class="n">stop</span><span class="p">()</span>
<span class="bp">self</span><span class="o">.</span><span class="n">amp</span><span class="o">.</span><span class="n">stop</span><span class="p">()</span>
<span class="bp">self</span><span class="o">.</span><span class="n">src</span><span class="o">.</span><span class="n">stop</span><span class="p">()</span>
<span class="bp">self</span><span class="o">.</span><span class="n">filt</span><span class="o">.</span><span class="n">stop</span><span class="p">()</span>
<span class="k">return</span> <span class="bp">self</span>
</pre></div>
</div>
</section>
<section id="control-attribute-with-numbers-instead-of-pyoobjects">
<h3>Control attribute with numbers instead of PyoObjects<a class="headerlink" href="#control-attribute-with-numbers-instead-of-pyoobjects" title="Permalink to this heading">¶</a></h3>
<p>Objects internal processing functions are optimized when plain numbers are
given to their attributes. Unless you really need audio control over some
parameters, don’t waste CPU cycles and give fixed numbers to every attribute
that don’t need to change over time. See this comparison:</p>
<div class="highlight-python notranslate"><div class="highlight"><pre><span></span><a class="sphinx-codeautolink-a" href="api/classes/generators.html#pyo.Noise" title="pyo.lib.generators.Noise"><span class="n">n</span></a> <span class="o">=</span> <a class="sphinx-codeautolink-a" href="api/classes/generators.html#pyo.Noise" title="pyo.lib.generators.Noise"><span class="n">Noise</span></a><span class="p">(</span><span class="mf">.2</span><span class="p">)</span>
<span class="c1"># ~5% CPU</span>
<span class="n">p1</span> <span class="o">=</span> <a class="sphinx-codeautolink-a" href="api/classes/filters.html#pyo.Phaser" title="pyo.lib.filters.Phaser"><span class="n">Phaser</span></a><span class="p">(</span><a class="sphinx-codeautolink-a" href="api/classes/generators.html#pyo.Noise" title="pyo.lib.generators.Noise"><span class="n">n</span></a><span class="p">,</span> <span class="n">freq</span><span class="o">=</span><span class="p">[</span><span class="mi">100</span><span class="p">,</span><span class="mi">105</span><span class="p">],</span> <span class="n">spread</span><span class="o">=</span><span class="mf">1.2</span><span class="p">,</span> <span class="n">q</span><span class="o">=</span><span class="mi">10</span><span class="p">,</span>
<span class="n">feedback</span><span class="o">=</span><span class="mf">0.9</span><span class="p">,</span> <span class="n">num</span><span class="o">=</span><span class="mi">48</span><span class="p">)</span><span class="o">.</span><span class="n">out</span><span class="p">()</span>
<span class="c1"># ~14% CPU</span>
<span class="n">p2</span> <span class="o">=</span> <a class="sphinx-codeautolink-a" href="api/classes/filters.html#pyo.Phaser" title="pyo.lib.filters.Phaser"><span class="n">Phaser</span></a><span class="p">(</span><a class="sphinx-codeautolink-a" href="api/classes/generators.html#pyo.Noise" title="pyo.lib.generators.Noise"><span class="n">n</span></a><span class="p">,</span> <span class="n">freq</span><span class="o">=</span><span class="p">[</span><span class="mi">100</span><span class="p">,</span><span class="mi">105</span><span class="p">],</span> <span class="n">spread</span><span class="o">=</span><a class="sphinx-codeautolink-a" href="api/classes/controls.html#pyo.Sig" title="pyo.lib._core.Sig"><span class="n">Sig</span></a><span class="p">(</span><span class="mf">1.2</span><span class="p">),</span> <span class="n">q</span><span class="o">=</span><span class="mi">10</span><span class="p">,</span>
<span class="n">feedback</span><span class="o">=</span><span class="mf">0.9</span><span class="p">,</span> <span class="n">num</span><span class="o">=</span><span class="mi">48</span><span class="p">)</span><span class="o">.</span><span class="n">out</span><span class="p">()</span>
</pre></div>
</div>
<p>Making the <cite>spread</cite> attribute of <cite>p2</cite> an audio signal causes the frequency of
the 48 notches to be recalculated every sample, which can be a very costly
process.</p>
</section>
<section id="check-for-denormal-numbers">
<h3>Check for denormal numbers<a class="headerlink" href="#check-for-denormal-numbers" title="Permalink to this heading">¶</a></h3>
<p>From wikipedia:</p>
<blockquote>
<div><p>In computer science, denormal numbers or denormalized numbers (now
often called subnormal numbers) fill the underflow gap around zero in
floating-point arithmetic. Any non-zero number with magnitude smaller
than the smallest normal number is ‘subnormal’.</p>
</div></blockquote>
<p>The problem is that some processors compute denormal numbers very
slowly, which makes grow the CPU consumption very quickly. The solution is to
wrap the objects that are subject to denormals (any object with an internal
recursive delay line, ie. filters, delays, reverbs, harmonizers, etc.) in a
<cite>Denorm</cite> object. <cite>Denorm</cite> adds a little amount of noise, with a magnitude
just above the smallest normal number, to its input. Of course, you can use
the same noise for multiple denormalizations:</p>
<div class="highlight-python notranslate"><div class="highlight"><pre><span></span><a class="sphinx-codeautolink-a" href="api/classes/generators.html#pyo.Noise" title="pyo.lib.generators.Noise"><span class="n">n</span></a> <span class="o">=</span> <a class="sphinx-codeautolink-a" href="api/classes/generators.html#pyo.Noise" title="pyo.lib.generators.Noise"><span class="n">Noise</span></a><span class="p">(</span><span class="mf">1e-24</span><span class="p">)</span> <span class="c1"># low-level noise for denormals</span>
<a class="sphinx-codeautolink-a" href="api/classes/players.html#pyo.SfPlayer" title="pyo.lib.players.SfPlayer"><span class="n">src</span></a> <span class="o">=</span> <a class="sphinx-codeautolink-a" href="api/classes/players.html#pyo.SfPlayer" title="pyo.lib.players.SfPlayer"><span class="n">SfPlayer</span></a><span class="p">(</span><span class="n">SNDS_PATH</span><span class="o">+</span><span class="s2">"/transparent.aif"</span><span class="p">)</span>
<span class="n">dly</span> <span class="o">=</span> <a class="sphinx-codeautolink-a" href="api/classes/effects.html#pyo.Delay" title="pyo.lib.effects.Delay"><span class="n">Delay</span></a><span class="p">(</span><a class="sphinx-codeautolink-a" href="api/classes/players.html#pyo.SfPlayer" title="pyo.lib.players.SfPlayer"><span class="n">src</span></a><span class="o">+</span><a class="sphinx-codeautolink-a" href="api/classes/generators.html#pyo.Noise" title="pyo.lib.generators.Noise"><span class="n">n</span></a><span class="p">,</span> <span class="n">delay</span><span class="o">=</span><span class="mf">.1</span><span class="p">,</span> <span class="n">feedback</span><span class="o">=</span><span class="mf">0.8</span><span class="p">,</span> <span class="n">mul</span><span class="o">=</span><span class="mf">0.2</span><span class="p">)</span><span class="o">.</span><span class="n">out</span><span class="p">()</span>
<span class="n">rev</span> <span class="o">=</span> <a class="sphinx-codeautolink-a" href="api/classes/effects.html#pyo.WGVerb" title="pyo.lib.effects.WGVerb"><span class="n">WGVerb</span></a><span class="p">(</span><a class="sphinx-codeautolink-a" href="api/classes/players.html#pyo.SfPlayer" title="pyo.lib.players.SfPlayer"><span class="n">src</span></a><span class="o">+</span><a class="sphinx-codeautolink-a" href="api/classes/generators.html#pyo.Noise" title="pyo.lib.generators.Noise"><span class="n">n</span></a><span class="p">)</span><span class="o">.</span><span class="n">out</span><span class="p">()</span>
</pre></div>
</div>
</section>
<section id="use-a-pyoobject-when-available">
<h3>Use a PyoObject when available<a class="headerlink" href="#use-a-pyoobject-when-available" title="Permalink to this heading">¶</a></h3>
<p>Always look first if a PyoObject does what you want, it will always be more
efficient than the same process written from scratch.</p>
<p>This construct, although pedagogically valid, will never be more efficient, in
term of CPU and memory usage, than a native PyoObject (Phaser) written in C.</p>
<div class="highlight-python notranslate"><div class="highlight"><pre><span></span><span class="n">a</span> <span class="o">=</span> <a class="sphinx-codeautolink-a" href="api/classes/generators.html#pyo.BrownNoise" title="pyo.lib.generators.BrownNoise"><span class="n">BrownNoise</span></a><span class="p">(</span><span class="mf">.02</span><span class="p">)</span><span class="o">.</span><span class="n">mix</span><span class="p">(</span><span class="mi">2</span><span class="p">)</span><span class="o">.</span><span class="n">out</span><span class="p">()</span>
<span class="n">lfo</span> <span class="o">=</span> <a class="sphinx-codeautolink-a" href="api/classes/generators.html#pyo.Sine" title="pyo.lib.generators.Sine"><span class="n">Sine</span></a><span class="p">(</span><span class="mf">.25</span><span class="p">)</span><span class="o">.</span><span class="n">range</span><span class="p">(</span><span class="mf">.75</span><span class="p">,</span> <span class="mf">1.25</span><span class="p">)</span>
<span class="n">filters</span> <span class="o">=</span> <span class="p">[]</span>
<span class="k">for</span> <span class="n">i</span> <span class="ow">in</span> <span class="nb">range</span><span class="p">(</span><span class="mi">24</span><span class="p">):</span>
<span class="n">freq</span> <span class="o">=</span> <a class="sphinx-codeautolink-a" href="api/functions/conv.html#pyo.rescale" title="pyo.rescale"><span class="n">rescale</span></a><span class="p">(</span><span class="n">i</span><span class="p">,</span> <span class="n">xmin</span><span class="o">=</span><span class="mi">0</span><span class="p">,</span> <span class="n">xmax</span><span class="o">=</span><span class="mi">24</span><span class="p">,</span> <span class="n">ymin</span><span class="o">=</span><span class="mi">100</span><span class="p">,</span> <span class="n">ymax</span><span class="o">=</span><span class="mi">10000</span><span class="p">)</span>
<span class="nb">filter</span> <span class="o">=</span> <a class="sphinx-codeautolink-a" href="api/classes/filters.html#pyo.Allpass2" title="pyo.lib.filters.Allpass2"><span class="n">Allpass2</span></a><span class="p">(</span><span class="n">a</span><span class="p">,</span> <span class="n">freq</span><span class="o">=</span><span class="n">lfo</span><span class="o">*</span><span class="n">freq</span><span class="p">,</span> <span class="n">bw</span><span class="o">=</span><span class="n">freq</span><span class="o">/</span><span class="mi">2</span><span class="p">,</span> <span class="n">mul</span><span class="o">=</span><span class="mf">0.2</span><span class="p">)</span><span class="o">.</span><span class="n">out</span><span class="p">()</span>
<span class="n">filters</span><span class="o">.</span><span class="n">append</span><span class="p">(</span><span class="nb">filter</span><span class="p">)</span>
</pre></div>
</div>
<p>It is also more efficient to use <cite>Biquadx(stages=4)</cite> than a cascade of four
<cite>Biquad</cite> objects with identical arguments.</p>
</section>
<section id="avoid-trigonometric-computation">
<h3>Avoid trigonometric computation<a class="headerlink" href="#avoid-trigonometric-computation" title="Permalink to this heading">¶</a></h3>
<p>Avoid trigonometric functions computed at audio rate (<cite>Sin</cite>, <cite>Cos</cite>, <cite>Tan</cite>,
<cite>Atan2</cite>, etc.), use simple approximations instead. For example, you can
replace a clean <cite>Sin/Cos</cite> panning function with a cheaper one based on <cite>Sqrt</cite>:</p>
<div class="highlight-python notranslate"><div class="highlight"><pre><span></span><span class="c1"># Heavier</span>
<span class="n">pan</span> <span class="o">=</span> <a class="sphinx-codeautolink-a" href="api/classes/controls.html#pyo.Linseg" title="pyo.lib.controls.Linseg"><span class="n">Linseg</span></a><span class="p">([(</span><span class="mi">0</span><span class="p">,</span><span class="mi">0</span><span class="p">),</span> <span class="p">(</span><span class="mi">2</span><span class="p">,</span> <span class="mi">1</span><span class="p">)])</span><span class="o">.</span><span class="n">play</span><span class="p">()</span>
<a class="sphinx-codeautolink-a" href="api/classes/arithmetic.html#pyo.Cos" title="pyo.lib.arithmetic.Cos"><span class="n">left</span></a> <span class="o">=</span> <a class="sphinx-codeautolink-a" href="api/classes/arithmetic.html#pyo.Cos" title="pyo.lib.arithmetic.Cos"><span class="n">Cos</span></a><span class="p">(</span><span class="n">pan</span> <span class="o">*</span> <span class="n">math</span><span class="o">.</span><span class="n">pi</span> <span class="o">*</span> <span class="mf">0.5</span><span class="p">,</span> <span class="n">mul</span><span class="o">=</span><span class="mf">0.5</span><span class="p">)</span>
<a class="sphinx-codeautolink-a" href="api/classes/arithmetic.html#pyo.Sin" title="pyo.lib.arithmetic.Sin"><span class="n">right</span></a> <span class="o">=</span> <a class="sphinx-codeautolink-a" href="api/classes/arithmetic.html#pyo.Sin" title="pyo.lib.arithmetic.Sin"><span class="n">Sin</span></a><span class="p">(</span><span class="n">pan</span> <span class="o">*</span> <span class="n">math</span><span class="o">.</span><span class="n">pi</span> <span class="o">*</span> <span class="mf">0.5</span><span class="p">,</span> <span class="n">mul</span><span class="o">=</span><span class="mf">0.5</span><span class="p">)</span>
<span class="n">a</span> <span class="o">=</span> <a class="sphinx-codeautolink-a" href="api/classes/generators.html#pyo.Noise" title="pyo.lib.generators.Noise"><span class="n">Noise</span></a><span class="p">([</span><a class="sphinx-codeautolink-a" href="api/classes/arithmetic.html#pyo.Cos" title="pyo.lib.arithmetic.Cos"><span class="n">left</span></a><span class="p">,</span> <a class="sphinx-codeautolink-a" href="api/classes/arithmetic.html#pyo.Sin" title="pyo.lib.arithmetic.Sin"><span class="n">right</span></a><span class="p">])</span><span class="o">.</span><span class="n">out</span><span class="p">()</span>
<span class="c1"># Cheaper</span>
<span class="n">pan2</span> <span class="o">=</span> <a class="sphinx-codeautolink-a" href="api/classes/controls.html#pyo.Linseg" title="pyo.lib.controls.Linseg"><span class="n">Linseg</span></a><span class="p">([(</span><span class="mi">0</span><span class="p">,</span><span class="mi">0</span><span class="p">),</span> <span class="p">(</span><span class="mi">2</span><span class="p">,</span> <span class="mi">1</span><span class="p">)])</span><span class="o">.</span><span class="n">play</span><span class="p">()</span>
<a class="sphinx-codeautolink-a" href="api/classes/arithmetic.html#pyo.Sqrt" title="pyo.lib.arithmetic.Sqrt"><span class="n">left2</span></a> <span class="o">=</span> <a class="sphinx-codeautolink-a" href="api/classes/arithmetic.html#pyo.Sqrt" title="pyo.lib.arithmetic.Sqrt"><span class="n">Sqrt</span></a><span class="p">(</span><span class="mi">1</span> <span class="o">-</span> <span class="n">pan2</span><span class="p">,</span> <span class="n">mul</span><span class="o">=</span><span class="mf">0.5</span><span class="p">)</span>
<a class="sphinx-codeautolink-a" href="api/classes/arithmetic.html#pyo.Sqrt" title="pyo.lib.arithmetic.Sqrt"><span class="n">right2</span></a> <span class="o">=</span> <a class="sphinx-codeautolink-a" href="api/classes/arithmetic.html#pyo.Sqrt" title="pyo.lib.arithmetic.Sqrt"><span class="n">Sqrt</span></a><span class="p">(</span><span class="n">pan2</span><span class="p">,</span> <span class="n">mul</span><span class="o">=</span><span class="mf">0.5</span><span class="p">)</span>
<span class="n">a2</span> <span class="o">=</span> <a class="sphinx-codeautolink-a" href="api/classes/generators.html#pyo.Noise" title="pyo.lib.generators.Noise"><span class="n">Noise</span></a><span class="p">([</span><a class="sphinx-codeautolink-a" href="api/classes/arithmetic.html#pyo.Sqrt" title="pyo.lib.arithmetic.Sqrt"><span class="n">left2</span></a><span class="p">,</span> <a class="sphinx-codeautolink-a" href="api/classes/arithmetic.html#pyo.Sqrt" title="pyo.lib.arithmetic.Sqrt"><span class="n">right2</span></a><span class="p">])</span><span class="o">.</span><span class="n">out</span><span class="p">()</span>
</pre></div>
</div>
</section>
<section id="use-approximations-if-absolute-precision-is-not-needed">
<h3>Use approximations if absolute precision is not needed<a class="headerlink" href="#use-approximations-if-absolute-precision-is-not-needed" title="Permalink to this heading">¶</a></h3>
<p>When absolute precision is not really important, you can save precious CPU
cycles by using approximations instead of the real function. <cite>FastSine</cite> is an
approximation of the <cite>sin</cite> function that can be almost twice cheaper than a
lookup table (Sine). I plan to add more approximations like this one in the
future.</p>
</section>
<section id="re-use-your-generators">
<h3>Re-use your generators<a class="headerlink" href="#re-use-your-generators" title="Permalink to this heading">¶</a></h3>
<p>Some times it possible to use the same signal for parallel purposes. Let’s
study the next process:</p>
<div class="highlight-python notranslate"><div class="highlight"><pre><span></span><span class="c1"># single white noise</span>
<a class="sphinx-codeautolink-a" href="api/classes/generators.html#pyo.Noise" title="pyo.lib.generators.Noise"><span class="n">noise</span></a> <span class="o">=</span> <a class="sphinx-codeautolink-a" href="api/classes/generators.html#pyo.Noise" title="pyo.lib.generators.Noise"><span class="n">Noise</span></a><span class="p">()</span>
<span class="c1"># denormal signal</span>
<span class="n">denorm</span> <span class="o">=</span> <a class="sphinx-codeautolink-a" href="api/classes/generators.html#pyo.Noise" title="pyo.lib.generators.Noise"><span class="n">noise</span></a> <span class="o">*</span> <span class="mf">1e-24</span>
<span class="c1"># little jitter around 1 used to modulate frequency</span>
<span class="n">jitter</span> <span class="o">=</span> <a class="sphinx-codeautolink-a" href="api/classes/generators.html#pyo.Noise" title="pyo.lib.generators.Noise"><span class="n">noise</span></a> <span class="o">*</span> <span class="mf">0.0007</span> <span class="o">+</span> <span class="mf">1.0</span>
<span class="c1"># excitation signal of the waveguide</span>
<span class="n">source</span> <span class="o">=</span> <a class="sphinx-codeautolink-a" href="api/classes/generators.html#pyo.Noise" title="pyo.lib.generators.Noise"><span class="n">noise</span></a> <span class="o">*</span> <span class="mf">0.7</span>
<span class="n">env</span> <span class="o">=</span> <a class="sphinx-codeautolink-a" href="api/classes/controls.html#pyo.Fader" title="pyo.lib.controls.Fader"><span class="n">Fader</span></a><span class="p">(</span><span class="n">fadein</span><span class="o">=</span><span class="mf">0.001</span><span class="p">,</span> <span class="n">fadeout</span><span class="o">=</span><span class="mf">0.01</span><span class="p">,</span> <span class="n">dur</span><span class="o">=</span><span class="mf">0.015</span><span class="p">)</span><span class="o">.</span><span class="n">play</span><span class="p">()</span>
<a class="sphinx-codeautolink-a" href="api/classes/filters.html#pyo.ButLP" title="pyo.lib.filters.ButLP"><span class="n">src</span></a> <span class="o">=</span> <a class="sphinx-codeautolink-a" href="api/classes/filters.html#pyo.ButLP" title="pyo.lib.filters.ButLP"><span class="n">ButLP</span></a><span class="p">(</span><span class="n">source</span><span class="p">,</span> <span class="n">freq</span><span class="o">=</span><span class="mi">1000</span><span class="p">,</span> <span class="n">mul</span><span class="o">=</span><span class="n">env</span><span class="p">)</span>
<span class="n">wg</span> <span class="o">=</span> <a class="sphinx-codeautolink-a" href="api/classes/effects.html#pyo.Waveguide" title="pyo.lib.effects.Waveguide"><span class="n">Waveguide</span></a><span class="p">(</span><a class="sphinx-codeautolink-a" href="api/classes/filters.html#pyo.ButLP" title="pyo.lib.filters.ButLP"><span class="n">src</span></a><span class="o">+</span><span class="n">denorm</span><span class="p">,</span> <span class="n">freq</span><span class="o">=</span><span class="mi">100</span><span class="o">*</span><span class="n">jitter</span><span class="p">,</span> <span class="n">dur</span><span class="o">=</span><span class="mi">30</span><span class="p">)</span><span class="o">.</span><span class="n">out</span><span class="p">()</span>
</pre></div>
</div>
<p>Here the same white noise is used for three purposes at the same time. First,
it is used to generate a denormal signal. Then, it is used to generate a
little jitter applied to the frequency of the waveguide (that adds a little
buzz to the string sound) and finally, we use it as the excitation of the
waveguide. This is surely cheaper than generating three different white noises
without noticeable difference in the sound.</p>
</section>
<section id="leave-mul-and-add-attributes-to-their-defaults-when-possible">
<h3>Leave ‘mul’ and ‘add’ attributes to their defaults when possible<a class="headerlink" href="#leave-mul-and-add-attributes-to-their-defaults-when-possible" title="Permalink to this heading">¶</a></h3>
<p>There is an internal condition that bypass the object “post-processing”
function when <cite>mul=1</cite> and <cite>add=0</cite>. It is a good practice to apply amplitude
control in one place instead of messing with the <cite>mul</cite> attribute of each
objects.</p>
<div class="highlight-python notranslate"><div class="highlight"><pre><span></span><span class="c1"># wrong</span>
<a class="sphinx-codeautolink-a" href="api/classes/generators.html#pyo.Noise" title="pyo.lib.generators.Noise"><span class="n">n</span></a> <span class="o">=</span> <a class="sphinx-codeautolink-a" href="api/classes/generators.html#pyo.Noise" title="pyo.lib.generators.Noise"><span class="n">Noise</span></a><span class="p">(</span><span class="n">mul</span><span class="o">=</span><span class="mf">0.7</span><span class="p">)</span>
<a class="sphinx-codeautolink-a" href="api/classes/filters.html#pyo.ButBP" title="pyo.lib.filters.ButBP"><span class="n">bp1</span></a> <span class="o">=</span> <a class="sphinx-codeautolink-a" href="api/classes/filters.html#pyo.ButBP" title="pyo.lib.filters.ButBP"><span class="n">ButBP</span></a><span class="p">(</span><a class="sphinx-codeautolink-a" href="api/classes/generators.html#pyo.Noise" title="pyo.lib.generators.Noise"><span class="n">n</span></a><span class="p">,</span> <span class="n">freq</span><span class="o">=</span><span class="mi">500</span><span class="p">,</span> <span class="n">q</span><span class="o">=</span><span class="mi">10</span><span class="p">,</span> <span class="n">mul</span><span class="o">=</span><span class="mf">0.5</span><span class="p">)</span>
<a class="sphinx-codeautolink-a" href="api/classes/filters.html#pyo.ButBP" title="pyo.lib.filters.ButBP"><span class="n">bp2</span></a> <span class="o">=</span> <a class="sphinx-codeautolink-a" href="api/classes/filters.html#pyo.ButBP" title="pyo.lib.filters.ButBP"><span class="n">ButBP</span></a><span class="p">(</span><a class="sphinx-codeautolink-a" href="api/classes/generators.html#pyo.Noise" title="pyo.lib.generators.Noise"><span class="n">n</span></a><span class="p">,</span> <span class="n">freq</span><span class="o">=</span><span class="mi">1500</span><span class="p">,</span> <span class="n">q</span><span class="o">=</span><span class="mi">10</span><span class="p">,</span> <span class="n">mul</span><span class="o">=</span><span class="mf">0.5</span><span class="p">)</span>
<a class="sphinx-codeautolink-a" href="api/classes/filters.html#pyo.ButBP" title="pyo.lib.filters.ButBP"><span class="n">bp3</span></a> <span class="o">=</span> <a class="sphinx-codeautolink-a" href="api/classes/filters.html#pyo.ButBP" title="pyo.lib.filters.ButBP"><span class="n">ButBP</span></a><span class="p">(</span><a class="sphinx-codeautolink-a" href="api/classes/generators.html#pyo.Noise" title="pyo.lib.generators.Noise"><span class="n">n</span></a><span class="p">,</span> <span class="n">freq</span><span class="o">=</span><span class="mi">2500</span><span class="p">,</span> <span class="n">q</span><span class="o">=</span><span class="mi">10</span><span class="p">,</span> <span class="n">mul</span><span class="o">=</span><span class="mf">0.5</span><span class="p">)</span>
<span class="n">rev</span> <span class="o">=</span> <a class="sphinx-codeautolink-a" href="api/classes/effects.html#pyo.Freeverb" title="pyo.lib.effects.Freeverb"><span class="n">Freeverb</span></a><span class="p">(</span><a class="sphinx-codeautolink-a" href="api/classes/filters.html#pyo.ButBP" title="pyo.lib.filters.ButBP"><span class="n">bp1</span></a><span class="o">+</span><a class="sphinx-codeautolink-a" href="api/classes/filters.html#pyo.ButBP" title="pyo.lib.filters.ButBP"><span class="n">bp2</span></a><span class="o">+</span><a class="sphinx-codeautolink-a" href="api/classes/filters.html#pyo.ButBP" title="pyo.lib.filters.ButBP"><span class="n">bp3</span></a><span class="p">,</span> <span class="n">size</span><span class="o">=</span><span class="mf">0.9</span><span class="p">,</span> <span class="n">bal</span><span class="o">=</span><span class="mf">0.3</span><span class="p">,</span> <span class="n">mul</span><span class="o">=</span><span class="mf">0.7</span><span class="p">)</span><span class="o">.</span><span class="n">out</span><span class="p">()</span>
<span class="c1"># good</span>
<a class="sphinx-codeautolink-a" href="api/classes/generators.html#pyo.Noise" title="pyo.lib.generators.Noise"><span class="n">n</span></a> <span class="o">=</span> <a class="sphinx-codeautolink-a" href="api/classes/generators.html#pyo.Noise" title="pyo.lib.generators.Noise"><span class="n">Noise</span></a><span class="p">(</span><span class="n">mul</span><span class="o">=</span><span class="mf">0.25</span><span class="p">)</span>
<a class="sphinx-codeautolink-a" href="api/classes/filters.html#pyo.ButBP" title="pyo.lib.filters.ButBP"><span class="n">bp1</span></a> <span class="o">=</span> <a class="sphinx-codeautolink-a" href="api/classes/filters.html#pyo.ButBP" title="pyo.lib.filters.ButBP"><span class="n">ButBP</span></a><span class="p">(</span><a class="sphinx-codeautolink-a" href="api/classes/generators.html#pyo.Noise" title="pyo.lib.generators.Noise"><span class="n">n</span></a><span class="p">,</span> <span class="n">freq</span><span class="o">=</span><span class="mi">500</span><span class="p">,</span> <span class="n">q</span><span class="o">=</span><span class="mi">10</span><span class="p">)</span>
<a class="sphinx-codeautolink-a" href="api/classes/filters.html#pyo.ButBP" title="pyo.lib.filters.ButBP"><span class="n">bp2</span></a> <span class="o">=</span> <a class="sphinx-codeautolink-a" href="api/classes/filters.html#pyo.ButBP" title="pyo.lib.filters.ButBP"><span class="n">ButBP</span></a><span class="p">(</span><a class="sphinx-codeautolink-a" href="api/classes/generators.html#pyo.Noise" title="pyo.lib.generators.Noise"><span class="n">n</span></a><span class="p">,</span> <span class="n">freq</span><span class="o">=</span><span class="mi">1500</span><span class="p">,</span> <span class="n">q</span><span class="o">=</span><span class="mi">10</span><span class="p">)</span>
<a class="sphinx-codeautolink-a" href="api/classes/filters.html#pyo.ButBP" title="pyo.lib.filters.ButBP"><span class="n">bp3</span></a> <span class="o">=</span> <a class="sphinx-codeautolink-a" href="api/classes/filters.html#pyo.ButBP" title="pyo.lib.filters.ButBP"><span class="n">ButBP</span></a><span class="p">(</span><a class="sphinx-codeautolink-a" href="api/classes/generators.html#pyo.Noise" title="pyo.lib.generators.Noise"><span class="n">n</span></a><span class="p">,</span> <span class="n">freq</span><span class="o">=</span><span class="mi">2500</span><span class="p">,</span> <span class="n">q</span><span class="o">=</span><span class="mi">10</span><span class="p">)</span>
<span class="n">rev</span> <span class="o">=</span> <a class="sphinx-codeautolink-a" href="api/classes/effects.html#pyo.Freeverb" title="pyo.lib.effects.Freeverb"><span class="n">Freeverb</span></a><span class="p">(</span><a class="sphinx-codeautolink-a" href="api/classes/filters.html#pyo.ButBP" title="pyo.lib.filters.ButBP"><span class="n">bp1</span></a><span class="o">+</span><a class="sphinx-codeautolink-a" href="api/classes/filters.html#pyo.ButBP" title="pyo.lib.filters.ButBP"><span class="n">bp2</span></a><span class="o">+</span><a class="sphinx-codeautolink-a" href="api/classes/filters.html#pyo.ButBP" title="pyo.lib.filters.ButBP"><span class="n">bp3</span></a><span class="p">,</span> <span class="n">size</span><span class="o">=</span><span class="mf">0.9</span><span class="p">,</span> <span class="n">bal</span><span class="o">=</span><span class="mf">0.3</span><span class="p">)</span><span class="o">.</span><span class="n">out</span><span class="p">()</span>
</pre></div>
</div>
</section>
<section id="avoid-graphical-updates">
<h3>Avoid graphical updates<a class="headerlink" href="#avoid-graphical-updates" title="Permalink to this heading">¶</a></h3>
<p>Even if they run in different threads, with different priorities, the audio
callback and the graphical interface of a python program are parts of a unique
process, sharing the same CPU. Don’t use the Server’s GUI if you don’t need to
see the meters or use the volume slider. Instead, you could start the script
from command line with <cite>-i</cite> flag to leave the interpreter alive.</p>
<div class="highlight-bash notranslate"><div class="highlight"><pre><span></span>$ python -i myscript.py
</pre></div>
</div>
</section>
<section id="list-of-cpu-intensive-objects">
<h3>List of CPU intensive objects<a class="headerlink" href="#list-of-cpu-intensive-objects" title="Permalink to this heading">¶</a></h3>
<p>Here is a non-exhaustive list of the most CPU intensive objects of the library.</p>
<ul class="simple">
<li><dl class="simple">
<dt>Analysis</dt><dd><ul>
<li><p>Yin</p></li>
<li><p>Centroid</p></li>
<li><p>Spectrum</p></li>
<li><p>Scope</p></li>
</ul>
</dd>
</dl>
</li>
<li><dl class="simple">
<dt>Arithmetic</dt><dd><ul>
<li><p>Sin</p></li>
<li><p>Cos</p></li>
<li><p>Tan</p></li>
<li><p>Tanh</p></li>
<li><p>Atan2</p></li>
</ul>
</dd>
</dl>
</li>
<li><dl class="simple">
<dt>Dynamic</dt><dd><ul>
<li><p>Compress</p></li>
<li><p>Gate</p></li>
</ul>
</dd>
</dl>
</li>
<li><dl class="simple">
<dt>Special Effects</dt><dd><ul>
<li><p>Convolve</p></li>
</ul>
</dd>
</dl>
</li>
<li><dl class="simple">
<dt>Prefix Expression Evaluator</dt><dd><ul>
<li><p>Expr</p></li>
</ul>
</dd>
</dl>
</li>
<li><dl class="simple">
<dt>Filters</dt><dd><ul>
<li><p>Phaser</p></li>
<li><p>Vocoder</p></li>
<li><p>IRWinSinc</p></li>
<li><p>IRAverage</p></li>
<li><p>IRPulse</p></li>
<li><p>IRFM</p></li>
</ul>
</dd>
</dl>
</li>
<li><dl class="simple">
<dt>Fast Fourier Transform</dt><dd><ul>
<li><p>CvlVerb</p></li>
</ul>
</dd>
</dl>
</li>
<li><dl class="simple">
<dt>Phase Vocoder</dt><dd><ul>
<li><p>Almost every objects!</p></li>
</ul>
</dd>
</dl>
</li>
<li><dl class="simple">
<dt>Signal Generators</dt><dd><ul>
<li><p>LFO</p></li>
</ul>
</dd>
</dl>
</li>
<li><dl class="simple">
<dt>Matrix Processing</dt><dd><ul>
<li><p>MatrixMorph</p></li>
</ul>
</dd>
</dl>
</li>
<li><dl class="simple">
<dt>Table Processing</dt><dd><ul>
<li><p>Granulator</p></li>
<li><p>Granule</p></li>
<li><p>Particule</p></li>
<li><p>OscBank</p></li>
</ul>
</dd>
</dl>
</li>
<li><dl class="simple">
<dt>Utilities</dt><dd><ul>
<li><p>Resample</p></li>
</ul>
</dd>
</dl>
</li>
</ul>
</section>
</section>
</section>
<div class="clearer"></div>
</div>
</div>
</div>
</div>
<div class="clearer"></div>
</div>
</div>
<div class="footer-wrapper">
<div class="footer">
<div class="left">
<div aria-label="related navigaton" role="navigation">
<a href="winaudioinspect.html" title="Configuring the audio output (Windows)">previous</a> |
<a href="api/index.html" title="API documentation">next</a> |
<a href="genindex.html" title="General Index">index</a>
</div>
<div aria-label="source link" role="note">
</div>
</div>
<div class="right">
<div class="footer" role="contentinfo">
© Copyright 2021, Olivier Bélanger.
Created using <a href="https://www.sphinx-doc.org/">Sphinx</a> 5.3.0.
</div>
</div>
<div class="clearer"></div>
</div>
</div>
</body>
</html>
|
