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
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
|
<!DOCTYPE html>
<html lang="en" data-content_root="../../" >
<head>
<meta charset="utf-8" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" /><meta name="viewport" content="width=device-width, initial-scale=1" />
<title>MatLoad — PETSc 3.22.5 documentation</title>
<script data-cfasync="false">
document.documentElement.dataset.mode = localStorage.getItem("mode") || "";
document.documentElement.dataset.theme = localStorage.getItem("theme") || "light";
</script>
<!-- Loaded before other Sphinx assets -->
<link href="../../_static/styles/theme.css?digest=bd9e20870c6007c4c509" rel="stylesheet" />
<link href="../../_static/styles/bootstrap.css?digest=bd9e20870c6007c4c509" rel="stylesheet" />
<link href="../../_static/styles/pydata-sphinx-theme.css?digest=bd9e20870c6007c4c509" rel="stylesheet" />
<link href="../../_static/vendor/fontawesome/6.5.1/css/all.min.css?digest=bd9e20870c6007c4c509" rel="stylesheet" />
<link rel="preload" as="font" type="font/woff2" crossorigin href="../../_static/vendor/fontawesome/6.5.1/webfonts/fa-solid-900.woff2" />
<link rel="preload" as="font" type="font/woff2" crossorigin href="../../_static/vendor/fontawesome/6.5.1/webfonts/fa-brands-400.woff2" />
<link rel="preload" as="font" type="font/woff2" crossorigin href="../../_static/vendor/fontawesome/6.5.1/webfonts/fa-regular-400.woff2" />
<link rel="stylesheet" type="text/css" href="../../_static/pygments.css?v=8f2a1f02" />
<link rel="stylesheet" type="text/css" href="../../_static/copybutton.css?v=76b2166b" />
<link rel="stylesheet" type="text/css" href="../../_static/sphinx-design.min.css?v=87e54e7c" />
<link rel="stylesheet" type="text/css" href="https://cdn.jsdelivr.net/npm/katex@0.16.10/dist/katex.min.css" />
<link rel="stylesheet" type="text/css" href="../../_static/katex-math.css?v=91adb8b6" />
<link rel="stylesheet" type="text/css" href="../../_static/css/custom.css?v=dbe1606d" />
<!-- Pre-loaded scripts that we'll load fully later -->
<link rel="preload" as="script" href="../../_static/scripts/bootstrap.js?digest=bd9e20870c6007c4c509" />
<link rel="preload" as="script" href="../../_static/scripts/pydata-sphinx-theme.js?digest=bd9e20870c6007c4c509" />
<script src="../../_static/vendor/fontawesome/6.5.1/js/all.min.js?digest=bd9e20870c6007c4c509"></script>
<script src="../../_static/documentation_options.js?v=988758ba"></script>
<script src="../../_static/doctools.js?v=9a2dae69"></script>
<script src="../../_static/sphinx_highlight.js?v=dc90522c"></script>
<script src="../../_static/clipboard.min.js?v=a7894cd8"></script>
<script src="../../_static/copybutton.js?v=a56c686a"></script>
<script src="../../_static/design-tabs.js?v=f930bc37"></script>
<script src="../../_static/katex.min.js?v=be8ff15f"></script>
<script src="../../_static/auto-render.min.js?v=ad136472"></script>
<script src="../../_static/katex_autorenderer.js?v=bebc588a"></script>
<script>DOCUMENTATION_OPTIONS.pagename = 'manualpages/Mat/MatLoad';</script>
<link rel="icon" href="../../_static/petsc_favicon.png"/>
<link rel="index" title="Index" href="../../genindex.html" />
<link rel="search" title="Search" href="../../search.html" />
<meta name="viewport" content="width=device-width, initial-scale=1"/>
<meta name="docsearch:language" content="en"/>
<meta name="docbuild:last-update" content="2025-03-28T16:05:55-0500 (v3.22.5)"/>
</head>
<body data-bs-spy="scroll" data-bs-target=".bd-toc-nav" data-offset="180" data-bs-root-margin="0px 0px -60%" data-default-mode="">
<a id="pst-skip-link" class="skip-link" href="#main-content">Skip to main content</a>
<div id="pst-scroll-pixel-helper"></div>
<button type="button" class="btn rounded-pill" id="pst-back-to-top">
<i class="fa-solid fa-arrow-up"></i>
Back to top
</button>
<input type="checkbox"
class="sidebar-toggle"
name="__primary"
id="__primary"/>
<label class="overlay overlay-primary" for="__primary"></label>
<input type="checkbox"
class="sidebar-toggle"
name="__secondary"
id="__secondary"/>
<label class="overlay overlay-secondary" for="__secondary"></label>
<div class="search-button__wrapper">
<div class="search-button__overlay"></div>
<div class="search-button__search-container">
<form class="bd-search d-flex align-items-center"
action="../../search.html"
method="get">
<i class="fa-solid fa-magnifying-glass"></i>
<input type="search"
class="form-control"
name="q"
id="search-input"
placeholder="Search the docs ..."
aria-label="Search the docs ..."
autocomplete="off"
autocorrect="off"
autocapitalize="off"
spellcheck="false"/>
<span class="search-button__kbd-shortcut"><kbd class="kbd-shortcut__modifier">Ctrl</kbd>+<kbd>K</kbd></span>
</form></div>
</div>
<header>
<div class="bd-header navbar navbar-expand-lg bd-navbar">
<div class="bd-header__inner bd-page-width">
<label class="sidebar-toggle primary-toggle" for="__primary">
<span class="fa-solid fa-bars"></span>
</label>
<div class="col-lg-3 navbar-header-items__start">
<div class="navbar-item">
<a class="navbar-brand logo" href="../../index.html">
<img src="../../_static/PETSc-TAO_RGB.svg" class="logo__image only-light" alt="PETSc 3.22.5 documentation - Home"/>
<script>document.write(`<img src="../../_static/PETSc-TAO_RGB_white.svg" class="logo__image only-dark" alt="PETSc 3.22.5 documentation - Home"/>`);</script>
</a></div>
</div>
<div class="col-lg-9 navbar-header-items">
<div class="me-auto navbar-header-items__center">
<div class="navbar-item">
<nav class="navbar-nav">
<ul class="bd-navbar-elements navbar-nav">
<li class="nav-item">
<a class="nav-link nav-internal" href="../../overview/index.html">
Overview
</a>
</li>
<li class="nav-item">
<a class="nav-link nav-internal" href="../../install/index.html">
Install
</a>
</li>
<li class="nav-item">
<a class="nav-link nav-internal" href="../../tutorials/index.html">
Tutorials
</a>
</li>
<li class="nav-item">
<a class="nav-link nav-internal" href="../../manual/index.html">
User-Guide
</a>
</li>
<li class="nav-item">
<a class="nav-link nav-internal" href="../index.html">
C/Fortran API
</a>
</li>
<li class="nav-item">
<a class="nav-link nav-internal" href="../../petsc4py/index.html">
petsc4py API
</a>
</li>
<li class="nav-item">
<a class="nav-link nav-internal" href="../../faq/index.html">
FAQ
</a>
</li>
<li class="nav-item">
<a class="nav-link nav-internal" href="../../community/index.html">
Community
</a>
</li>
<li class="nav-item">
<a class="nav-link nav-internal" href="../../developers/index.html">
Developers
</a>
</li>
<li class="nav-item">
<a class="nav-link nav-internal" href="../../miscellaneous/index.html">
Misc.
</a>
</li>
</ul>
</nav></div>
</div>
<div class="navbar-header-items__end">
<div class="navbar-item navbar-persistent--container">
<script>
document.write(`
<button class="btn navbar-btn search-button-field search-button__button" title="Search" aria-label="Search" data-bs-placement="bottom" data-bs-toggle="tooltip">
<i class="fa-solid fa-magnifying-glass"></i>
<span class="search-button__default-text">Search</span>
<span class="search-button__kbd-shortcut"><kbd class="kbd-shortcut__modifier">Ctrl</kbd>+<kbd class="kbd-shortcut__modifier">K</kbd></span>
</button>
`);
</script>
</div>
<div class="navbar-item">
<script>
document.write(`
<button class="btn btn-sm navbar-btn theme-switch-button" title="light/dark" aria-label="light/dark" data-bs-placement="bottom" data-bs-toggle="tooltip">
<span class="theme-switch nav-link" data-mode="light"><i class="fa-solid fa-sun fa-lg"></i></span>
<span class="theme-switch nav-link" data-mode="dark"><i class="fa-solid fa-moon fa-lg"></i></span>
<span class="theme-switch nav-link" data-mode="auto"><i class="fa-solid fa-circle-half-stroke fa-lg"></i></span>
</button>
`);
</script></div>
<div class="navbar-item"><ul class="navbar-icon-links navbar-nav"
aria-label="Icon Links">
<li class="nav-item">
<a href="https://gitlab.com/petsc/petsc" title="GitLab" class="nav-link" rel="noopener" target="_blank" data-bs-toggle="tooltip" data-bs-placement="bottom"><span><i class="fab fa-gitlab fa-lg" aria-hidden="true"></i></span>
<span class="sr-only">GitLab</span></a>
</li>
</ul></div>
</div>
</div>
<div class="navbar-persistent--mobile">
<script>
document.write(`
<button class="btn navbar-btn search-button-field search-button__button" title="Search" aria-label="Search" data-bs-placement="bottom" data-bs-toggle="tooltip">
<i class="fa-solid fa-magnifying-glass"></i>
<span class="search-button__default-text">Search</span>
<span class="search-button__kbd-shortcut"><kbd class="kbd-shortcut__modifier">Ctrl</kbd>+<kbd class="kbd-shortcut__modifier">K</kbd></span>
</button>
`);
</script>
</div>
<label class="sidebar-toggle secondary-toggle" for="__secondary" tabindex="0">
<span class="fa-solid fa-outdent"></span>
</label>
</div>
</div>
</header>
<div class="bd-container">
<div class="bd-container__inner bd-page-width">
<div class="bd-sidebar-primary bd-sidebar hide-on-wide">
<div class="sidebar-header-items sidebar-primary__section">
<div class="sidebar-header-items__center">
<div class="navbar-item">
<nav class="navbar-nav">
<ul class="bd-navbar-elements navbar-nav">
<li class="nav-item">
<a class="nav-link nav-internal" href="../../overview/index.html">
Overview
</a>
</li>
<li class="nav-item">
<a class="nav-link nav-internal" href="../../install/index.html">
Install
</a>
</li>
<li class="nav-item">
<a class="nav-link nav-internal" href="../../tutorials/index.html">
Tutorials
</a>
</li>
<li class="nav-item">
<a class="nav-link nav-internal" href="../../manual/index.html">
User-Guide
</a>
</li>
<li class="nav-item">
<a class="nav-link nav-internal" href="../index.html">
C/Fortran API
</a>
</li>
<li class="nav-item">
<a class="nav-link nav-internal" href="../../petsc4py/index.html">
petsc4py API
</a>
</li>
<li class="nav-item">
<a class="nav-link nav-internal" href="../../faq/index.html">
FAQ
</a>
</li>
<li class="nav-item">
<a class="nav-link nav-internal" href="../../community/index.html">
Community
</a>
</li>
<li class="nav-item">
<a class="nav-link nav-internal" href="../../developers/index.html">
Developers
</a>
</li>
<li class="nav-item">
<a class="nav-link nav-internal" href="../../miscellaneous/index.html">
Misc.
</a>
</li>
</ul>
</nav></div>
</div>
<div class="sidebar-header-items__end">
<div class="navbar-item">
<script>
document.write(`
<button class="btn btn-sm navbar-btn theme-switch-button" title="light/dark" aria-label="light/dark" data-bs-placement="bottom" data-bs-toggle="tooltip">
<span class="theme-switch nav-link" data-mode="light"><i class="fa-solid fa-sun fa-lg"></i></span>
<span class="theme-switch nav-link" data-mode="dark"><i class="fa-solid fa-moon fa-lg"></i></span>
<span class="theme-switch nav-link" data-mode="auto"><i class="fa-solid fa-circle-half-stroke fa-lg"></i></span>
</button>
`);
</script></div>
<div class="navbar-item"><ul class="navbar-icon-links navbar-nav"
aria-label="Icon Links">
<li class="nav-item">
<a href="https://gitlab.com/petsc/petsc" title="GitLab" class="nav-link" rel="noopener" target="_blank" data-bs-toggle="tooltip" data-bs-placement="bottom"><span><i class="fab fa-gitlab fa-lg" aria-hidden="true"></i></span>
<span class="sr-only">GitLab</span></a>
</li>
</ul></div>
</div>
</div>
<div class="sidebar-primary-items__end sidebar-primary__section">
</div>
<div id="rtd-footer-container"></div>
</div>
<main id="main-content" class="bd-main">
<div class="bd-content">
<div class="bd-article-container">
<div class="bd-header-article">
<div class="header-article-items header-article__inner">
<div class="header-article-items__start">
<div class="header-article-item">
<nav aria-label="Breadcrumb">
<ul class="bd-breadcrumbs">
<li class="breadcrumb-item breadcrumb-home">
<a href="../../index.html" class="nav-link" aria-label="Home">
<i class="fa-solid fa-home"></i>
</a>
</li>
<li class="breadcrumb-item active" aria-current="page">MatLoad</li>
</ul>
</nav>
</div>
</div>
</div>
</div>
<div id="searchbox"></div>
<article class="bd-article">
<section class="tex2jax_ignore mathjax_ignore" id="matload">
<h1>MatLoad<a class="headerlink" href="#matload" title="Link to this heading">#</a></h1>
<p>Loads a matrix that has been stored in binary/HDF5 format with <code class="docutils notranslate"><span class="pre"><a href="../../manualpages/Mat/MatView.html">MatView</a>()</span></code>. The matrix format is determined from the options database. Generates a parallel MPI matrix if the communicator has more than one processor. The default matrix type is <code class="docutils notranslate"><span class="pre"><a href="../../manualpages/Mat/MATAIJ.html">MATAIJ</a></span></code>.</p>
<section id="synopsis">
<h2>Synopsis<a class="headerlink" href="#synopsis" title="Link to this heading">#</a></h2>
<div class="highlight-c notranslate"><div class="highlight"><pre><span></span><span class="cp">#include</span><span class="w"> </span><span class="cpf">"petscmat.h"</span><span class="c1"> </span>
<span class="n"><a href="../../manualpages/Sys/PetscErrorCode.html">PetscErrorCode</a></span><span class="w"> </span><span class="n"><a href="../../manualpages/Mat/MatLoad.html">MatLoad</a></span><span class="p">(</span><span class="n"><a href="../../manualpages/Mat/Mat.html">Mat</a></span><span class="w"> </span><span class="n">mat</span><span class="p">,</span><span class="w"> </span><span class="n"><a href="../../manualpages/Viewer/PetscViewer.html">PetscViewer</a></span><span class="w"> </span><span class="n">viewer</span><span class="p">)</span>
</pre></div>
</div>
<p>Collective</p>
</section>
<section id="input-parameters">
<h2>Input Parameters<a class="headerlink" href="#input-parameters" title="Link to this heading">#</a></h2>
<ul class="simple">
<li><p><em><strong>mat -</strong></em> the newly loaded matrix, this needs to have been created with <code class="docutils notranslate"><span class="pre"><a href="../../manualpages/Mat/MatCreate.html">MatCreate</a>()</span></code>
or some related function before a call to <code class="docutils notranslate"><span class="pre"><a href="../../manualpages/Mat/MatLoad.html">MatLoad</a>()</span></code></p></li>
<li><p><em><strong>viewer -</strong></em> <code class="docutils notranslate"><span class="pre"><a href="../../manualpages/Viewer/PETSCVIEWERBINARY.html">PETSCVIEWERBINARY</a></span></code>/<code class="docutils notranslate"><span class="pre"><a href="../../manualpages/Viewer/PETSCVIEWERHDF5.html">PETSCVIEWERHDF5</a></span></code> file viewer</p></li>
</ul>
</section>
<section id="options-database-key">
<h2>Options Database Key<a class="headerlink" href="#options-database-key" title="Link to this heading">#</a></h2>
<ul class="simple">
<li><p><em><strong>-matload_block_size <bs> -</strong></em> set block size</p></li>
</ul>
</section>
<section id="notes">
<h2>Notes<a class="headerlink" href="#notes" title="Link to this heading">#</a></h2>
<p>If the <code class="docutils notranslate"><span class="pre"><a href="../../manualpages/Mat/Mat.html">Mat</a></span></code> type has not yet been given then <code class="docutils notranslate"><span class="pre"><a href="../../manualpages/Mat/MATAIJ.html">MATAIJ</a></span></code> is used, call <code class="docutils notranslate"><span class="pre"><a href="../../manualpages/Mat/MatSetFromOptions.html">MatSetFromOptions</a>()</span></code> on the
<code class="docutils notranslate"><span class="pre"><a href="../../manualpages/Mat/Mat.html">Mat</a></span></code> before calling this routine if you wish to set it from the options database.</p>
<p><code class="docutils notranslate"><span class="pre"><a href="../../manualpages/Mat/MatLoad.html">MatLoad</a>()</span></code> automatically loads into the options database any options
given in the file filename.info where filename is the name of the file
that was passed to the <code class="docutils notranslate"><span class="pre"><a href="../../manualpages/Viewer/PetscViewerBinaryOpen.html">PetscViewerBinaryOpen</a>()</span></code>. The options in the info
file will be ignored if you use the -viewer_binary_skip_info option.</p>
<p>If the type or size of mat is not set before a call to <code class="docutils notranslate"><span class="pre"><a href="../../manualpages/Mat/MatLoad.html">MatLoad</a>()</span></code>, PETSc
sets the default matrix type AIJ and sets the local and global sizes.
If type and/or size is already set, then the same are used.</p>
<p>In parallel, each processor can load a subset of rows (or the
entire matrix). This routine is especially useful when a large
matrix is stored on disk and only part of it is desired on each
processor. For example, a parallel solver may access only some of
the rows from each processor. The algorithm used here reads
relatively small blocks of data rather than reading the entire
matrix and then subsetting it.</p>
<p>Viewer’s <code class="docutils notranslate"><span class="pre"><a href="../../manualpages/Viewer/PetscViewerType.html">PetscViewerType</a></span></code> must be either <code class="docutils notranslate"><span class="pre"><a href="../../manualpages/Viewer/PETSCVIEWERBINARY.html">PETSCVIEWERBINARY</a></span></code> or <code class="docutils notranslate"><span class="pre"><a href="../../manualpages/Viewer/PETSCVIEWERHDF5.html">PETSCVIEWERHDF5</a></span></code>.
Such viewer can be created using <code class="docutils notranslate"><span class="pre"><a href="../../manualpages/Viewer/PetscViewerBinaryOpen.html">PetscViewerBinaryOpen</a>()</span></code> or <code class="docutils notranslate"><span class="pre"><a href="../../manualpages/Viewer/PetscViewerHDF5Open.html">PetscViewerHDF5Open</a>()</span></code>,
or the sequence like</p>
<div class="highlight-none notranslate"><div class="highlight"><pre><span></span> `<a href="../../manualpages/Viewer/PetscViewer.html">PetscViewer</a>` v;
`<a href="../../manualpages/Viewer/PetscViewerCreate.html">PetscViewerCreate</a>`(`<a href="../../manualpages/Sys/PETSC_COMM_WORLD.html">PETSC_COMM_WORLD</a>`,&v);
`<a href="../../manualpages/Viewer/PetscViewerSetType.html">PetscViewerSetType</a>`(v,`<a href="../../manualpages/Viewer/PETSCVIEWERBINARY.html">PETSCVIEWERBINARY</a>`);
`<a href="../../manualpages/Viewer/PetscViewerSetFromOptions.html">PetscViewerSetFromOptions</a>`(v);
`<a href="../../manualpages/Viewer/PetscViewerFileSetMode.html">PetscViewerFileSetMode</a>`(v,`<a href="../../manualpages/Sys/PetscFileMode.html">FILE_MODE_READ</a>`);
`<a href="../../manualpages/Viewer/PetscViewerFileSetName.html">PetscViewerFileSetName</a>`(v,"datafile");
</pre></div>
</div>
<p>The optional <code class="docutils notranslate"><span class="pre"><a href="../../manualpages/Viewer/PetscViewerSetFromOptions.html">PetscViewerSetFromOptions</a>()</span></code> call allows overriding <code class="docutils notranslate"><span class="pre"><a href="../../manualpages/Viewer/PetscViewerSetType.html">PetscViewerSetType</a>()</span></code> using the option</p>
<div class="highlight-none notranslate"><div class="highlight"><pre><span></span>-viewer_type {binary, hdf5}
</pre></div>
</div>
<p>See the example src/ksp/ksp/tutorials/ex27.c with the first approach,
and src/mat/tutorials/ex10.c with the second approach.</p>
<p>In case of <code class="docutils notranslate"><span class="pre"><a href="../../manualpages/Viewer/PETSCVIEWERBINARY.html">PETSCVIEWERBINARY</a></span></code>, a native PETSc binary format is used. Each of the blocks
is read onto MPI rank 0 and then shipped to its destination MPI rank, one after another.
Multiple objects, both matrices and vectors, can be stored within the same file.
Their <code class="docutils notranslate"><span class="pre"><a href="../../manualpages/Sys/PetscObject.html">PetscObject</a></span></code> name is ignored; they are loaded in the order of their storage.</p>
<p>Most users should not need to know the details of the binary storage
format, since <code class="docutils notranslate"><span class="pre"><a href="../../manualpages/Mat/MatLoad.html">MatLoad</a>()</span></code> and <code class="docutils notranslate"><span class="pre"><a href="../../manualpages/Mat/MatView.html">MatView</a>()</span></code> completely hide these details.
But for anyone who is interested, the standard binary matrix storage
format is</p>
<div class="highlight-none notranslate"><div class="highlight"><pre><span></span> <a href="../../manualpages/Sys/PetscInt.html">PetscInt</a> MAT_FILE_CLASSID
<a href="../../manualpages/Sys/PetscInt.html">PetscInt</a> number of rows
<a href="../../manualpages/Sys/PetscInt.html">PetscInt</a> number of columns
<a href="../../manualpages/Sys/PetscInt.html">PetscInt</a> total number of nonzeros
<a href="../../manualpages/Sys/PetscInt.html">PetscInt</a> *number nonzeros in each row
<a href="../../manualpages/Sys/PetscInt.html">PetscInt</a> *column indices of all nonzeros (starting index is zero)
<a href="../../manualpages/Sys/PetscScalar.html">PetscScalar</a> *values of all nonzeros
</pre></div>
</div>
<p>If PETSc was not configured with <code class="docutils notranslate"><span class="pre">--with-64-bit-indices</span></code> then only <code class="docutils notranslate"><span class="pre"><a href="../../manualpages/Mat/MATMPIAIJ.html">MATMPIAIJ</a></span></code> matrices with more than <code class="docutils notranslate"><span class="pre">PETSC_INT_MAX</span></code> non-zeros can be
stored or loaded (each MPI process part of the matrix must have less than <code class="docutils notranslate"><span class="pre">PETSC_INT_MAX</span></code> nonzeros). Since the total nonzero count in this
case will not fit in a (32-bit) <code class="docutils notranslate"><span class="pre"><a href="../../manualpages/Sys/PetscInt.html">PetscInt</a></span></code> the value <code class="docutils notranslate"><span class="pre">PETSC_INT_MAX</span></code> is used for the header entry <code class="docutils notranslate"><span class="pre">total</span> <span class="pre">number</span> <span class="pre">of</span> <span class="pre">nonzeros</span></code>.</p>
<p>PETSc automatically does the byte swapping for
machines that store the bytes reversed. Thus if you write your own binary
read/write routines you have to swap the bytes; see <code class="docutils notranslate"><span class="pre"><a href="../../manualpages/Sys/PetscBinaryRead.html">PetscBinaryRead</a>()</span></code>
and <code class="docutils notranslate"><span class="pre"><a href="../../manualpages/Sys/PetscBinaryWrite.html">PetscBinaryWrite</a>()</span></code> to see how this may be done.</p>
<p>In case of <code class="docutils notranslate"><span class="pre"><a href="../../manualpages/Viewer/PETSCVIEWERHDF5.html">PETSCVIEWERHDF5</a></span></code>, a parallel HDF5 reader is used.
Each processor’s chunk is loaded independently by its owning MPI process.
Multiple objects, both matrices and vectors, can be stored within the same file.
They are looked up by their PetscObject name.</p>
<p>As the MATLAB MAT-File Version 7.3 format is also a HDF5 flavor, we decided to use
by default the same structure and naming of the AIJ arrays and column count
within the HDF5 file. This means that a MAT file saved with -v7.3 flag, e.g.</p>
<div class="highlight-none notranslate"><div class="highlight"><pre><span></span>save example.mat A b -v7.3
</pre></div>
</div>
<p>can be directly read by this routine (see Reference 1 for details).</p>
<p>Depending on your MATLAB version, this format might be a default,
otherwise you can set it as default in Preferences.</p>
<p>Unless -nocompression flag is used to save the file in MATLAB,
PETSc must be configured with ZLIB package.</p>
<p>See also examples src/mat/tutorials/ex10.c and src/ksp/ksp/tutorials/ex27.c</p>
<p>This reader currently supports only real <code class="docutils notranslate"><span class="pre"><a href="../../manualpages/Mat/MATSEQAIJ.html">MATSEQAIJ</a></span></code>, <code class="docutils notranslate"><span class="pre"><a href="../../manualpages/Mat/MATMPIAIJ.html">MATMPIAIJ</a></span></code>, <code class="docutils notranslate"><span class="pre"><a href="../../manualpages/Mat/MATSEQDENSE.html">MATSEQDENSE</a></span></code> and <code class="docutils notranslate"><span class="pre"><a href="../../manualpages/Mat/MATMPIDENSE.html">MATMPIDENSE</a></span></code> matrices for <code class="docutils notranslate"><span class="pre"><a href="../../manualpages/Viewer/PETSCVIEWERHDF5.html">PETSCVIEWERHDF5</a></span></code></p>
<p>Corresponding <code class="docutils notranslate"><span class="pre"><a href="../../manualpages/Mat/MatView.html">MatView</a>()</span></code> is not yet implemented.</p>
<p>The loaded matrix is actually a transpose of the original one in MATLAB,
unless you push <code class="docutils notranslate"><span class="pre"><a href="../../manualpages/Viewer/PetscViewerFormat.html">PETSC_VIEWER_HDF5_MAT</a></span></code> format (see examples above).
With this format, matrix is automatically transposed by PETSc,
unless the matrix is marked as SPD or symmetric
(see <code class="docutils notranslate"><span class="pre"><a href="../../manualpages/Mat/MatSetOption.html">MatSetOption</a>()</span></code>, <code class="docutils notranslate"><span class="pre"><a href="../../manualpages/Mat/MatOption.html">MAT_SPD</a></span></code>, <code class="docutils notranslate"><span class="pre"><a href="../../manualpages/Mat/MatOption.html">MAT_SYMMETRIC</a></span></code>).</p>
<p>See MATLAB Documentation on <code class="docutils notranslate"><span class="pre">save()</span></code>, <a class="reference external" href="https://www.mathworks.com/help/matlab/ref/save.html#btox10b-1-version">https://www.mathworks.com/help/matlab/ref/save.html#btox10b-1-version</a></p>
</section>
<section id="see-also">
<h2>See Also<a class="headerlink" href="#see-also" title="Link to this heading">#</a></h2>
<p><a class="reference internal" href="../../manual/mat.html#ch-matrices"><span class="std std-ref">Matrices</span></a>, <code class="docutils notranslate"><span class="pre"><a href="../../manualpages/Mat/Mat.html">Mat</a></span></code>, <code class="docutils notranslate"><span class="pre"><a href="../../manualpages/Viewer/PetscViewerBinaryOpen.html">PetscViewerBinaryOpen</a>()</span></code>, <code class="docutils notranslate"><span class="pre"><a href="../../manualpages/Viewer/PetscViewerSetType.html">PetscViewerSetType</a>()</span></code>, <code class="docutils notranslate"><span class="pre"><a href="../../manualpages/Mat/MatView.html">MatView</a>()</span></code>, <code class="docutils notranslate"><span class="pre"><a href="../../manualpages/Vec/VecLoad.html">VecLoad</a>()</span></code></p>
</section>
<section id="level">
<h2>Level<a class="headerlink" href="#level" title="Link to this heading">#</a></h2>
<p>beginner</p>
</section>
<section id="location">
<h2>Location<a class="headerlink" href="#location" title="Link to this heading">#</a></h2>
<p><A HREF="../../src/mat/interface/matrix.c.html#MatLoad">src/mat/interface/matrix.c</A></p>
</section>
<section id="examples">
<h2>Examples<a class="headerlink" href="#examples" title="Link to this heading">#</a></h2>
<p><A HREF="../../src/ksp/ksp/tutorials/ex87.c.html">src/ksp/ksp/tutorials/ex87.c</A><BR>
<A HREF="../../src/ksp/ksp/tutorials/ex77.c.html">src/ksp/ksp/tutorials/ex77.c</A><BR>
<A HREF="../../src/ksp/ksp/tutorials/ex75.c.html">src/ksp/ksp/tutorials/ex75.c</A><BR>
<A HREF="../../src/ksp/ksp/tutorials/ex10.c.html">src/ksp/ksp/tutorials/ex10.c</A><BR>
<A HREF="../../src/ksp/ksp/tutorials/ex27.c.html">src/ksp/ksp/tutorials/ex27.c</A><BR>
<A HREF="../../src/ksp/ksp/tutorials/ex72.c.html">src/ksp/ksp/tutorials/ex72.c</A><BR>
<A HREF="../../src/ksp/ksp/tutorials/ex77f.F90.html">src/ksp/ksp/tutorials/ex77f.F90</A><BR>
<A HREF="../../src/ksp/ksp/tutorials/ex41.c.html">src/ksp/ksp/tutorials/ex41.c</A><BR>
<A HREF="../../src/ksp/ksp/tutorials/ex75f.F90.html">src/ksp/ksp/tutorials/ex75f.F90</A><BR>
<A HREF="../../src/ksp/ksp/tutorials/ex76f.F90.html">src/ksp/ksp/tutorials/ex76f.F90</A><BR></p>
</section>
<section id="implementations">
<h2>Implementations<a class="headerlink" href="#implementations" title="Link to this heading">#</a></h2>
<p><A HREF="../../src/mat/impls/aij/mpi/mpiaij.c.html#MatLoad_MPIAIJ">MatLoad_MPIAIJ() in src/mat/impls/aij/mpi/mpiaij.c</A><BR>
<A HREF="../../src/mat/impls/aij/seq/aij.c.html#MatLoad_SeqAIJ">MatLoad_SeqAIJ() in src/mat/impls/aij/seq/aij.c</A><BR>
<A HREF="../../src/mat/impls/baij/mpi/mpibaij.c.html#MatLoad_MPIBAIJ">MatLoad_MPIBAIJ() in src/mat/impls/baij/mpi/mpibaij.c</A><BR>
<A HREF="../../src/mat/impls/baij/seq/baij.c.html#MatLoad_SeqBAIJ">MatLoad_SeqBAIJ() in src/mat/impls/baij/seq/baij.c</A><BR>
<A HREF="../../src/mat/impls/blockmat/seq/blockmat.c.html#MatLoad_BlockMat">MatLoad_BlockMat() in src/mat/impls/blockmat/seq/blockmat.c</A><BR>
<A HREF="../../src/mat/impls/dense/mpi/mpidense.c.html#MatLoad_MPIDense">MatLoad_MPIDense() in src/mat/impls/dense/mpi/mpidense.c</A><BR>
<A HREF="../../src/mat/impls/dense/seq/dense.c.html#MatLoad_SeqDense">MatLoad_SeqDense() in src/mat/impls/dense/seq/dense.c</A><BR>
<A HREF="../../src/mat/impls/elemental/matelem.cxx.html#MatLoad_Elemental">MatLoad_Elemental() in src/mat/impls/elemental/matelem.cxx</A><BR>
<A HREF="../../src/mat/impls/is/matis.c.html#MatLoad_IS">MatLoad_IS() in src/mat/impls/is/matis.c</A><BR>
<A HREF="../../src/mat/impls/sbaij/mpi/mpisbaij.c.html#MatLoad_MPISBAIJ">MatLoad_MPISBAIJ() in src/mat/impls/sbaij/mpi/mpisbaij.c</A><BR>
<A HREF="../../src/mat/impls/sbaij/seq/sbaij.c.html#MatLoad_SeqSBAIJ">MatLoad_SeqSBAIJ() in src/mat/impls/sbaij/seq/sbaij.c</A><BR>
<A HREF="../../src/mat/impls/scalapack/matscalapack.c.html#MatLoad_ScaLAPACK">MatLoad_ScaLAPACK() in src/mat/impls/scalapack/matscalapack.c</A><BR></p>
<hr class="docutils" />
<p><a class="reference internal" href="index.html"><span class="std std-doc">Index of all Mat routines</span></a><br />
<a class="reference internal" href="../index.html"><span class="std std-doc">Table of Contents for all manual pages</span></a><br />
<a class="reference internal" href="../singleindex.html"><span class="std std-doc">Index of all manual pages</span></a></p>
</section>
</section>
</article>
<footer class="prev-next-footer">
<div class="prev-next-area">
</div>
</footer>
</div>
<div class="bd-sidebar-secondary bd-toc"><div class="sidebar-secondary-items sidebar-secondary__inner">
<div class="sidebar-secondary-item">
<div
id="pst-page-navigation-heading-2"
class="page-toc tocsection onthispage">
<i class="fa-solid fa-list"></i> On this page
</div>
<nav class="bd-toc-nav page-toc" aria-labelledby="pst-page-navigation-heading-2">
<ul class="visible nav section-nav flex-column">
<li class="toc-h2 nav-item toc-entry"><a class="reference internal nav-link" href="#synopsis">Synopsis</a></li>
<li class="toc-h2 nav-item toc-entry"><a class="reference internal nav-link" href="#input-parameters">Input Parameters</a></li>
<li class="toc-h2 nav-item toc-entry"><a class="reference internal nav-link" href="#options-database-key">Options Database Key</a></li>
<li class="toc-h2 nav-item toc-entry"><a class="reference internal nav-link" href="#notes">Notes</a></li>
<li class="toc-h2 nav-item toc-entry"><a class="reference internal nav-link" href="#see-also">See Also</a></li>
<li class="toc-h2 nav-item toc-entry"><a class="reference internal nav-link" href="#level">Level</a></li>
<li class="toc-h2 nav-item toc-entry"><a class="reference internal nav-link" href="#location">Location</a></li>
<li class="toc-h2 nav-item toc-entry"><a class="reference internal nav-link" href="#examples">Examples</a></li>
<li class="toc-h2 nav-item toc-entry"><a class="reference internal nav-link" href="#implementations">Implementations</a></li>
</ul>
</nav></div>
<div class="sidebar-secondary-item">
<div class="tocsection editthispage">
<a href=https://gitlab.com/petsc/petsc/-/edit/release/src/mat/interface/matrix.c>
<i class="fa-solid fa-pencil"></i>
Edit on GitLab
</a>
</div>
</div>
<div class="sidebar-secondary-item">
<div class="tocsection sourcelink">
<a href="../../_sources/manualpages/Mat/MatLoad.md.txt">
<i class="fa-solid fa-file-lines"></i> Show Source
</a>
</div>
</div>
</div></div>
</div>
<footer class="bd-footer-content">
</footer>
</main>
</div>
</div>
<!-- Scripts loaded after <body> so the DOM is not blocked -->
<script src="../../_static/scripts/bootstrap.js?digest=bd9e20870c6007c4c509"></script>
<script src="../../_static/scripts/pydata-sphinx-theme.js?digest=bd9e20870c6007c4c509"></script>
<footer class="bd-footer">
<div class="bd-footer__inner bd-page-width">
<div class="footer-items__start">
<div class="footer-item">
<p class="copyright">
© Copyright 1991-2025, UChicago Argonne, LLC and the PETSc Development Team.
<br/>
</p>
</div>
<div class="footer-item">
<p class="sphinx-version">
Created using <a href="https://www.sphinx-doc.org/">Sphinx</a> 7.3.7.
<br/>
</p>
</div>
</div>
<div class="footer-items__end">
<div class="footer-item">
<p class="theme-version">
Built with the <a href="https://pydata-sphinx-theme.readthedocs.io/en/stable/index.html">PyData Sphinx Theme</a> 0.15.1.
</p></div>
<div class="footer-item"><p class="last-updated">
Last updated on 2025-03-28T16:05:55-0500 (v3.22.5).
<br/>
</p></div>
</div>
</div>
</footer>
</body>
</html>
|
