/usr/share/doc/mathgl/mathgl_en/mathgl_en_17.html is in mathgl-doc-en 2.1.3.1-4ubuntu3.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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 | <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html401/loose.dtd">
<html>
<!-- This manual is for MathGL (version 2.1.2), a collection of classes and routines for scientific plotting. Please report any errors in this manual to mathgl.abalakin@gmail.org.
Copyright C 2008-2012 Alexey A. Balakin.
Permission is granted to copy, distribute and/or modify this document
under the terms of the GNU Free Documentation License, Version 1.2
or any later version published by the Free Software Foundation;
with no Invariant Sections, no Front-Cover Texts, and no Back-Cover
Texts. A copy of the license is included in the section entitled "GNU
Free Documentation License."
-->
<!-- Created on December 22, 2013 by texi2html 1.82
texi2html was written by:
Lionel Cons <Lionel.Cons@cern.ch> (original author)
Karl Berry <karl@freefriends.org>
Olaf Bachmann <obachman@mathematik.uni-kl.de>
and many others.
Maintained by: Many creative people.
Send bugs and suggestions to <texi2html-bug@nongnu.org>
-->
<head>
<title>MathGL 2.1.2: 2.8 Vector field samples</title>
<meta name="description" content="MathGL 2.1.2: 2.8 Vector field samples">
<meta name="keywords" content="MathGL 2.1.2: 2.8 Vector field samples">
<meta name="resource-type" content="document">
<meta name="distribution" content="global">
<meta name="Generator" content="texi2html 1.82">
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<style type="text/css">
<!--
a.summary-letter {text-decoration: none}
blockquote.smallquotation {font-size: smaller}
pre.display {font-family: serif}
pre.format {font-family: serif}
pre.menu-comment {font-family: serif}
pre.menu-preformatted {font-family: serif}
pre.smalldisplay {font-family: serif; font-size: smaller}
pre.smallexample {font-size: smaller}
pre.smallformat {font-family: serif; font-size: smaller}
pre.smalllisp {font-size: smaller}
span.roman {font-family:serif; font-weight:normal;}
span.sansserif {font-family:sans-serif; font-weight:normal;}
ul.toc {list-style: none}
-->
</style>
</head>
<body lang="en" bgcolor="#FFFFFF" text="#000000" link="#0000FF" vlink="#800080" alink="#FF0000">
<a name="Vector-field-samples"></a>
<table cellpadding="1" cellspacing="1" border="0">
<tr><td valign="middle" align="left">[<a href="mathgl_en_16.html#Dots-sample" title="Previous section in reading order"> < </a>]</td>
<td valign="middle" align="left">[<a href="#Vect-sample" title="Next section in reading order"> > </a>]</td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left">[<a href="mathgl_en_9.html#Examples" title="Beginning of this chapter or previous chapter"> << </a>]</td>
<td valign="middle" align="left">[<a href="mathgl_en_9.html#Examples" title="Up section"> Up </a>]</td>
<td valign="middle" align="left">[<a href="mathgl_en_20.html#General-concepts" title="Next chapter"> >> </a>]</td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left">[<a href="mathgl_en.html#Top" title="Cover (top) of document">Top</a>]</td>
<td valign="middle" align="left">[<a href="mathgl_en_toc.html#SEC_Contents" title="Table of contents">Contents</a>]</td>
<td valign="middle" align="left">[<a href="mathgl_en_88.html#Index" title="Index">Index</a>]</td>
<td valign="middle" align="left">[<a href="mathgl_en_abt.html#SEC_About" title="About (help)"> ? </a>]</td>
</tr></table>
<a name="Vector-field-samples-1"></a>
<h2 class="section">2.8 Vector field samples</h2>
<p>Vector field visualization (especially in 3d case) is more or less complex task. MathGL provides 3 general types of plots: vector field itself (<code>Vect</code>), flow threads (<code>Flow</code>), and flow pipes with radius proportional to field amplitude (<code>Pipe</code>).
</p>
<p>However, the plot may look tangly – there are too many overlapping lines. I may suggest 2 ways to solve this problem. The first one is to change <code>SetMeshNum</code> for decreasing the number of hachures. The second way is to use the flow thread chart <code>Flow</code>, or possible many flow thread from manual position (<code>FlowP</code>). Unfortunately, I don’t know any other methods to visualize 3d vector field. If you know any, e-mail me and I shall add it to MathGL.
</p>
<p>Most of samples will use the same data for plotting. So, I put its initialization in separate function
</p><pre class="verbatim">void mgls_prepare2v(mglData *a, mglData *b)
{
register long i,j,n=20,m=30,i0;
if(a) a->Create(n,m); if(b) b->Create(n,m);
mreal x,y;
for(i=0;i<n;i++) for(j=0;j<m;j++)
{
x=i/(n-1.); y=j/(m-1.); i0 = i+n*j;
if(a) a->a[i0] = 0.6*sin(2*M_PI*x)*sin(3*M_PI*y)+0.4*cos(3*M_PI*x*y);
if(b) b->a[i0] = 0.6*cos(2*M_PI*x)*cos(3*M_PI*y)+0.4*cos(3*M_PI*x*y);
}
}
void mgls_prepare3v(mglData *ex, mglData *ey, mglData *ez)
{
register long i,j,k,n=10,i0;
if(!ex || !ey || !ez) return;
ex->Create(n,n,n); ey->Create(n,n,n); ez->Create(n,n,n);
mreal x,y,z, r1,r2;
for(i=0;i<n;i++) for(j=0;j<n;j++) for(k=0;k<n;k++)
{
x=2*i/(n-1.)-1; y=2*j/(n-1.)-1; z=2*k/(n-1.)-1; i0 = i+n*(j+k*n);
r1 = pow(x*x+y*y+(z-0.3)*(z-0.3)+0.03,1.5);
r2 = pow(x*x+y*y+(z+0.3)*(z+0.3)+0.03,1.5);
ex->a[i0]=0.2*x/r1 - 0.2*x/r2;
ey->a[i0]=0.2*y/r1 - 0.2*y/r2;
ez->a[i0]=0.2*(z-0.3)/r1 - 0.2*(z+0.3)/r2;
}
}
</pre><p>or using C functions
</p><pre class="verbatim">void mgls_prepare2v(HMDT a, HMDT b)
{
register long i,j,n=20,m=30,i0;
if(a) mgl_data_create(a,n,m,1);
if(b) mgl_data_create(b,n,m,1);
mreal x,y;
for(i=0;i<n;i++) for(j=0;j<m;j++)
{
x=i/(n-1.); y=j/(m-1.); i0 = i+n*j;
if(a) mgl_data_set_value(a, 0.6*sin(2*M_PI*x)*sin(3*M_PI*y)+0.4*cos(3*M_PI*x*y), i,j,0);
if(b) mgl_data_set_value(b, 0.6*cos(2*M_PI*x)*cos(3*M_PI*y)+0.4*cos(3*M_PI*x*y), i,j,0);
}
}
void mgls_prepare3v(HMDT ex, HMDT ey, HMDT ez)
{
register long i,j,k,n=10,i0;
if(!ex || !ey || !ez) return;
mgl_data_create(ex,n,n,n);
mgl_data_create(ey,n,n,n);
mgl_data_create(ez,n,n,n);
mreal x,y,z, r1,r2;
for(i=0;i<n;i++) for(j=0;j<n;j++) for(k=0;k<n;k++)
{
x=2*i/(n-1.)-1; y=2*j/(n-1.)-1; z=2*k/(n-1.)-1; i0 = i+n*(j+k*n);
r1 = pow(x*x+y*y+(z-0.3)*(z-0.3)+0.03,1.5);
r2 = pow(x*x+y*y+(z+0.3)*(z+0.3)+0.03,1.5);
mgl_data_set_value(ex, 0.2*x/r1 - 0.2*x/r2, i,j,k);
mgl_data_set_value(ey, 0.2*y/r1 - 0.2*y/r2, i,j,k);
mgl_data_set_value(ez, 0.2*(z-0.3)/r1 - 0.2*(z+0.3)/r2, i,j,k);
}
}
</pre>
<table class="menu" border="0" cellspacing="0">
<tr><td align="left" valign="top"><a href="#Vect-sample">2.8.1 Vect sample</a></td><td> </td><td align="left" valign="top">
</td></tr>
<tr><td align="left" valign="top"><a href="#Vect3-sample">2.8.2 Vect3 sample</a></td><td> </td><td align="left" valign="top">
</td></tr>
<tr><td align="left" valign="top"><a href="#Traj-sample">2.8.3 Traj sample</a></td><td> </td><td align="left" valign="top">
</td></tr>
<tr><td align="left" valign="top"><a href="#Flow-sample">2.8.4 Flow sample</a></td><td> </td><td align="left" valign="top">
</td></tr>
<tr><td align="left" valign="top"><a href="#Pipe-sample">2.8.5 Pipe sample</a></td><td> </td><td align="left" valign="top">
</td></tr>
<tr><td align="left" valign="top"><a href="#Dew-sample">2.8.6 Dew sample</a></td><td> </td><td align="left" valign="top">
</td></tr>
</table>
<hr size="6">
<a name="Vect-sample"></a>
<table cellpadding="1" cellspacing="1" border="0">
<tr><td valign="middle" align="left">[<a href="#Vector-field-samples" title="Previous section in reading order"> < </a>]</td>
<td valign="middle" align="left">[<a href="#Vect3-sample" title="Next section in reading order"> > </a>]</td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left">[<a href="mathgl_en_9.html#Examples" title="Beginning of this chapter or previous chapter"> << </a>]</td>
<td valign="middle" align="left">[<a href="#Vector-field-samples" title="Up section"> Up </a>]</td>
<td valign="middle" align="left">[<a href="mathgl_en_20.html#General-concepts" title="Next chapter"> >> </a>]</td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left">[<a href="mathgl_en.html#Top" title="Cover (top) of document">Top</a>]</td>
<td valign="middle" align="left">[<a href="mathgl_en_toc.html#SEC_Contents" title="Table of contents">Contents</a>]</td>
<td valign="middle" align="left">[<a href="mathgl_en_88.html#Index" title="Index">Index</a>]</td>
<td valign="middle" align="left">[<a href="mathgl_en_abt.html#SEC_About" title="About (help)"> ? </a>]</td>
</tr></table>
<a name="Vect-sample-1"></a>
<h3 class="subsection">2.8.1 Vect sample</h3>
<p>Function <a href="mathgl_en_43.html#vect">vect</a> is most standard way to visualize vector fields – it draw a lot of arrows or hachures for each data cell. It have a lot of options which can be seen on the figure (and in the sample code). <code>Vect</code> use color scheme for coloring (see <a href="mathgl_en_24.html#Color-scheme">Color scheme</a>). The sample code is:
</p><pre class="verbatim">int sample(mglGraph *gr)
{
mglData a,b; mgls_prepare2v(&a,&b);
gr->SubPlot(3,2,0,""); gr->Title("Vect plot (default)");
gr->Box(); gr->Vect(a,b);
gr->SubPlot(3,2,1,""); gr->Title("'.' style; '=' style");
gr->Box(); gr->Vect(a,b,"=.");
gr->SubPlot(3,2,2,""); gr->Title("'f' style");
gr->Box(); gr->Vect(a,b,"f");
gr->SubPlot(3,2,3,""); gr->Title("'>' style");
gr->Box(); gr->Vect(a,b,">");
gr->SubPlot(3,2,4,""); gr->Title("'<' style");
gr->Box(); gr->Vect(a,b,"<");
mglData ex,ey,ez; mgls_prepare3v(&ex,&ey,&ez);
gr->SubPlot(3,2,5); gr->Title("3d variant"); gr->Rotate(50,60);
gr->Box(); gr->Vect(ex,ey,ez);
return 0;
}
</pre>
<img src="../png/vect.png" alt="Example of Vect()">
<hr size="6">
<a name="Vect3-sample"></a>
<table cellpadding="1" cellspacing="1" border="0">
<tr><td valign="middle" align="left">[<a href="#Vect-sample" title="Previous section in reading order"> < </a>]</td>
<td valign="middle" align="left">[<a href="#Traj-sample" title="Next section in reading order"> > </a>]</td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left">[<a href="mathgl_en_9.html#Examples" title="Beginning of this chapter or previous chapter"> << </a>]</td>
<td valign="middle" align="left">[<a href="#Vector-field-samples" title="Up section"> Up </a>]</td>
<td valign="middle" align="left">[<a href="mathgl_en_20.html#General-concepts" title="Next chapter"> >> </a>]</td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left">[<a href="mathgl_en.html#Top" title="Cover (top) of document">Top</a>]</td>
<td valign="middle" align="left">[<a href="mathgl_en_toc.html#SEC_Contents" title="Table of contents">Contents</a>]</td>
<td valign="middle" align="left">[<a href="mathgl_en_88.html#Index" title="Index">Index</a>]</td>
<td valign="middle" align="left">[<a href="mathgl_en_abt.html#SEC_About" title="About (help)"> ? </a>]</td>
</tr></table>
<a name="Vect3-sample-1"></a>
<h3 class="subsection">2.8.2 Vect3 sample</h3>
<p>Function <a href="mathgl_en_43.html#vect3">vect3</a> draw just usual vector field plot but at slices of 3D data. The sample code is:
</p><pre class="verbatim">int sample(mglGraph *gr)
{
mglData ex,ey,ez; mgls_prepare3v(&ex,&ey,&ez);
gr->SubPlot(2,1,0); gr->Title("Vect3 sample"); gr->SetOrigin(0,0,0);
gr->Rotate(50,60); gr->Axis("_xyz"); gr->Box();
gr->Vect3(ex,ey,ez,"x"); gr->Vect3(ex,ey,ez); gr->Vect3(ex,ey,ez,"z");
gr->SubPlot(2,1,1); gr->Title("'f' style");
gr->Rotate(50,60); gr->Axis("_xyz"); gr->Box();
gr->Vect3(ex,ey,ez,"fx"); gr->Vect3(ex,ey,ez,"f");gr->Vect3(ex,ey,ez,"fz");
gr->Grid3(ex,"Wx"); gr->Grid3(ex,"W"); gr->Grid3(ex,"Wz");
return 0;
}
</pre>
<img src="../png/vecta.png" alt="Example of Vect3()">
<hr size="6">
<a name="Traj-sample"></a>
<table cellpadding="1" cellspacing="1" border="0">
<tr><td valign="middle" align="left">[<a href="#Vect3-sample" title="Previous section in reading order"> < </a>]</td>
<td valign="middle" align="left">[<a href="#Flow-sample" title="Next section in reading order"> > </a>]</td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left">[<a href="mathgl_en_9.html#Examples" title="Beginning of this chapter or previous chapter"> << </a>]</td>
<td valign="middle" align="left">[<a href="#Vector-field-samples" title="Up section"> Up </a>]</td>
<td valign="middle" align="left">[<a href="mathgl_en_20.html#General-concepts" title="Next chapter"> >> </a>]</td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left">[<a href="mathgl_en.html#Top" title="Cover (top) of document">Top</a>]</td>
<td valign="middle" align="left">[<a href="mathgl_en_toc.html#SEC_Contents" title="Table of contents">Contents</a>]</td>
<td valign="middle" align="left">[<a href="mathgl_en_88.html#Index" title="Index">Index</a>]</td>
<td valign="middle" align="left">[<a href="mathgl_en_abt.html#SEC_About" title="About (help)"> ? </a>]</td>
</tr></table>
<a name="Traj-sample-1"></a>
<h3 class="subsection">2.8.3 Traj sample</h3>
<p>Function <a href="mathgl_en_43.html#traj">traj</a> is 1D analogue of <code>Vect</code>. It draw vectors from specified points. The sample code is:
</p><pre class="verbatim">int sample(mglGraph *gr)
{
mglData x,y,y1,y2; mgls_prepare1d(&y,&y1,&y2,&x);
gr->SubPlot(1,1,0,""); gr->Title("Traj plot");
gr->Box(); gr->Plot(x,y); gr->Traj(x,y,y1,y2);
return 0;
}
</pre>
<img src="../png/traj.png" alt="Example of Traj()">
<hr size="6">
<a name="Flow-sample"></a>
<table cellpadding="1" cellspacing="1" border="0">
<tr><td valign="middle" align="left">[<a href="#Traj-sample" title="Previous section in reading order"> < </a>]</td>
<td valign="middle" align="left">[<a href="#Pipe-sample" title="Next section in reading order"> > </a>]</td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left">[<a href="mathgl_en_9.html#Examples" title="Beginning of this chapter or previous chapter"> << </a>]</td>
<td valign="middle" align="left">[<a href="#Vector-field-samples" title="Up section"> Up </a>]</td>
<td valign="middle" align="left">[<a href="mathgl_en_20.html#General-concepts" title="Next chapter"> >> </a>]</td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left">[<a href="mathgl_en.html#Top" title="Cover (top) of document">Top</a>]</td>
<td valign="middle" align="left">[<a href="mathgl_en_toc.html#SEC_Contents" title="Table of contents">Contents</a>]</td>
<td valign="middle" align="left">[<a href="mathgl_en_88.html#Index" title="Index">Index</a>]</td>
<td valign="middle" align="left">[<a href="mathgl_en_abt.html#SEC_About" title="About (help)"> ? </a>]</td>
</tr></table>
<a name="Flow-sample-1"></a>
<h3 class="subsection">2.8.4 Flow sample</h3>
<p>Function <a href="mathgl_en_43.html#flow">flow</a> is another standard way to visualize vector fields – it draw lines (threads) which is tangent to local vector field direction. MathGL draw threads from edges of bounding box and from central slices. Sometimes it is not most appropriate variant – you may want to use <code>FlowP</code> to specify manual position of threads. <code>Flow</code> use color scheme for coloring (see <a href="mathgl_en_24.html#Color-scheme">Color scheme</a>). At this warm color corresponds to normal flow (like attractor), cold one corresponds to inverse flow (like source). The sample code is:
</p><pre class="verbatim">int sample(mglGraph *gr)
{
mglData a,b; mgls_prepare2v(&a,&b);
gr->SubPlot(2,2,0,""); gr->Title("Flow plot (default)");
gr->Box(); gr->Flow(a,b);
gr->SubPlot(2,2,1,""); gr->Title("'v' style");
gr->Box(); gr->Flow(a,b,"v");
gr->SubPlot(2,2,2,""); gr->Title("'\\#' style");
gr->Box(); gr->Flow(a,b,"#");
mglData ex,ey,ez; mgls_prepare3v(&ex,&ey,&ez);
gr->SubPlot(2,2,3); gr->Title("3d variant"); gr->Rotate(50,60);
gr->Box(); gr->Flow(ex,ey,ez);
return 0;
}
</pre>
<img src="../png/flow.png" alt="Example of Flow()">
<hr size="6">
<a name="Pipe-sample"></a>
<table cellpadding="1" cellspacing="1" border="0">
<tr><td valign="middle" align="left">[<a href="#Flow-sample" title="Previous section in reading order"> < </a>]</td>
<td valign="middle" align="left">[<a href="#Dew-sample" title="Next section in reading order"> > </a>]</td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left">[<a href="mathgl_en_9.html#Examples" title="Beginning of this chapter or previous chapter"> << </a>]</td>
<td valign="middle" align="left">[<a href="#Vector-field-samples" title="Up section"> Up </a>]</td>
<td valign="middle" align="left">[<a href="mathgl_en_20.html#General-concepts" title="Next chapter"> >> </a>]</td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left">[<a href="mathgl_en.html#Top" title="Cover (top) of document">Top</a>]</td>
<td valign="middle" align="left">[<a href="mathgl_en_toc.html#SEC_Contents" title="Table of contents">Contents</a>]</td>
<td valign="middle" align="left">[<a href="mathgl_en_88.html#Index" title="Index">Index</a>]</td>
<td valign="middle" align="left">[<a href="mathgl_en_abt.html#SEC_About" title="About (help)"> ? </a>]</td>
</tr></table>
<a name="Pipe-sample-1"></a>
<h3 class="subsection">2.8.5 Pipe sample</h3>
<p>Function <a href="mathgl_en_43.html#pipe">pipe</a> is similar to <a href="mathgl_en_43.html#flow">flow</a> but draw pipes (tubes) which radius is proportional to the amplitude of vector field. <code>Pipe</code> use color scheme for coloring (see <a href="mathgl_en_24.html#Color-scheme">Color scheme</a>). At this warm color corresponds to normal flow (like attractor), cold one corresponds to inverse flow (like source). The sample code is:
</p><pre class="verbatim">int sample(mglGraph *gr)
{
mglData a,b; mgls_prepare2v(&a,&b);
gr->SubPlot(2,2,0,""); gr->Title("Pipe plot (default)");
gr->Light(true); gr->Box(); gr->Pipe(a,b);
gr->SubPlot(2,2,1,""); gr->Title("'i' style");
gr->Box(); gr->Pipe(a,b,"i");
gr->SubPlot(2,2,2,""); gr->Title("'\\#' style");
gr->Box(); gr->Pipe(a,b,"#");
mglData ex,ey,ez; mgls_prepare3v(&ex,&ey,&ez);
gr->SubPlot(2,2,3); gr->Title("3d variant"); gr->Rotate(50,60);
gr->Box(); gr->Pipe(ex,ey,ez,"",0.1);
return 0;
}
</pre>
<img src="../png/pipe.png" alt="Example of Pipe()">
<hr size="6">
<a name="Dew-sample"></a>
<table cellpadding="1" cellspacing="1" border="0">
<tr><td valign="middle" align="left">[<a href="#Pipe-sample" title="Previous section in reading order"> < </a>]</td>
<td valign="middle" align="left">[<a href="mathgl_en_18.html#Hints" title="Next section in reading order"> > </a>]</td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left">[<a href="mathgl_en_9.html#Examples" title="Beginning of this chapter or previous chapter"> << </a>]</td>
<td valign="middle" align="left">[<a href="#Vector-field-samples" title="Up section"> Up </a>]</td>
<td valign="middle" align="left">[<a href="mathgl_en_20.html#General-concepts" title="Next chapter"> >> </a>]</td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left">[<a href="mathgl_en.html#Top" title="Cover (top) of document">Top</a>]</td>
<td valign="middle" align="left">[<a href="mathgl_en_toc.html#SEC_Contents" title="Table of contents">Contents</a>]</td>
<td valign="middle" align="left">[<a href="mathgl_en_88.html#Index" title="Index">Index</a>]</td>
<td valign="middle" align="left">[<a href="mathgl_en_abt.html#SEC_About" title="About (help)"> ? </a>]</td>
</tr></table>
<a name="Dew-sample-1"></a>
<h3 class="subsection">2.8.6 Dew sample</h3>
<p>Function <a href="mathgl_en_43.html#dew">dew</a> is similar to <code>Vect</code> but use drops instead of arrows. The sample code is:
</p><pre class="verbatim">int sample(mglGraph *gr)
{
mglData a,b; mgls_prepare2v(&a,&b);
gr->SubPlot(1,1,0,""); gr->Title("Dew plot");
gr->Box(); gr->Light(true); gr->Dew(a,b);
return 0;
}
</pre>
<img src="../png/dew.png" alt="Example of Dew()">
<hr size="6">
<table cellpadding="1" cellspacing="1" border="0">
<tr><td valign="middle" align="left">[<a href="#Pipe-sample" title="Previous section in reading order"> < </a>]</td>
<td valign="middle" align="left">[<a href="mathgl_en_18.html#Hints" title="Next section in reading order"> > </a>]</td>
<td valign="middle" align="left"> </td>
<td valign="middle" align="left">[<a href="mathgl_en_9.html#Examples" title="Beginning of this chapter or previous chapter"> << </a>]</td>
<td valign="middle" align="left">[<a href="#Vector-field-samples" title="Up section"> Up </a>]</td>
<td valign="middle" align="left">[<a href="mathgl_en_20.html#General-concepts" title="Next chapter"> >> </a>]</td>
</tr></table>
<p>
<font size="-1">
This document was generated by <em>Build Daemon user</em> on <em>December 22, 2013</em> using <a href="http://www.nongnu.org/texi2html/"><em>texi2html 1.82</em></a>.
</font>
<br>
</p>
</body>
</html>
|