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
|
//---------------------------------------------------------------------------//
// $Id: x04.java,v 1.14 2005/07/03 12:43:39 andrewross Exp $
//---------------------------------------------------------------------------//
//---------------------------------------------------------------------------//
// Copyright (C) 2001 Geoffrey Furnish
// Copyright (C) 2001, 2002 Alan W. Irwin
// Copyright (C) 2004 Andrew Ross
//
// This file is part of PLplot.
//
// PLplot is free software; you can redistribute it and/or modify
// it under the terms of the GNU Library General Public License as published by
// the Free Software Foundation; version 2 of the License.
//
// PLplot is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Library General Public License for more details.
//
// You should have received a copy of the GNU Library General Public License
// along with PLplot; if not, write to the Free Software
// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
//---------------------------------------------------------------------------//
//---------------------------------------------------------------------------//
// Implementation of PLplot example 4 in Java.
//---------------------------------------------------------------------------//
package plplot.examples;
import plplot.core.*;
import java.lang.Math;
class x04 {
PLStream pls = new PLStream();
public static void main( String[] args )
{
x04 x = new x04( args );
}
public x04( String[] args )
{
// Parse and process command line arguments.
pls.parseopts( args, PLStream.PL_PARSE_FULL | PLStream.PL_PARSE_NOPROGRAM );
// Initialize plplot.
pls.init();
pls.font(2);
// Make log plots using two different styles.
plot1(0);
plot1(1);
pls.end();
}
// Log-linear plot.
void plot1( int type )
{
int i;
double[] freql = new double[101];
double[] ampl = new double[101];
double[] phase = new double[101];
double f0, freq;
pls.adv(0);
// Set up data for log plot.
f0 = 1.0;
for (i = 0; i <= 100; i++) {
freql[i] = -2.0 + i / 20.0;
freq = Math.pow(10.0, freql[i]);
// Unbelievably, Java has no log10() that I can find...
ampl[i] = 20.0 * Math.log(1.0 / Math.sqrt(1.0 + Math.pow((freq / f0), 2.))) / Math.log(10.);
phase[i] = -(180.0 / Math.PI) * Math.atan(freq / f0);
}
pls.vpor(0.15, 0.85, 0.1, 0.9);
pls.wind(-2.0, 3.0, -80.0, 0.0);
// Try different axis and labelling styles.
pls.col0(1);
switch (type) {
case 0:
pls.box("bclnst", 0.0, 0, "bnstv", 0.0, 0);
break;
case 1:
pls.box("bcfghlnst", 0.0, 0, "bcghnstv", 0.0, 0);
break;
}
// Plot ampl vs freq.
pls.col0(2);
pls.line(freql, ampl);
pls.col0(1);
pls.ptex(1.6, -30.0, 1.0, -20.0, 0.5, "-20 dB/decade");
// Put labels on.
pls.col0(1);
pls.mtex("b", 3.2, 0.5, 0.5, "Frequency");
pls.mtex("t", 2.0, 0.5, 0.5, "Single Pole Low-Pass Filter");
pls.col0(2);
pls.mtex("l", 5.0, 0.5, 0.5, "Amplitude (dB)");
// For the gridless case, put phase vs freq on same plot.
if (type == 0) {
pls.col0(1);
pls.wind(-2.0, 3.0, -100.0, 0.0);
pls.box("", 0.0, 0, "cmstv", 30.0, 3);
pls.col0(3);
pls.line(freql, phase);
pls.col0(3);
pls.mtex("r", 5.0, 0.5, 0.5, "Phase shift (degrees)");
}
}
}
//---------------------------------------------------------------------------//
// End of x04.java
//---------------------------------------------------------------------------//
|
