/usr/share/doc/libplplot12/examples/c++/x09.cc is in libplplot-dev 5.10.0+dfsg-1.
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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 | //--------------------------------------------------------------------------
// $Id: x09.cc 12176 2012-02-24 20:33:39Z andrewross $
//--------------------------------------------------------------------------
//
//--------------------------------------------------------------------------
// Copyright (C) 2004 Andrew Ross
// Copyright (C) 2004 Alan W. Irwin
//
// 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 09 in C++.
//--------------------------------------------------------------------------
#include "plc++demos.h"
#ifdef PL_USE_NAMESPACE
using namespace std;
#endif
class x09 {
public:
x09( int, const char** );
void polar();
void potential();
private:
plstream *pls;
static const int XPTS;
static const int YPTS;
// polar plot data
static const int PERIMETERPTS;
static const int RPTS;
static const int THETAPTS;
// potential plot data
static const int PPERIMETERPTS;
static const int PRPTS;
static const int PTHETAPTS;
static const int PNLEVEL;
static PLFLT clevel[];
// Transformation function
// static const PLFLT tr[];
public:
static const PLFLT XSPA;
static const PLFLT YSPA;
};
const int x09:: XPTS = 35;
const int x09:: YPTS = 46;
const PLFLT x09::XSPA = 2. / ( XPTS - 1 );
const PLFLT x09::YSPA = 2. / ( YPTS - 1 );
// polar plot data
const int x09::PERIMETERPTS = 100;
const int x09::RPTS = 40;
const int x09::THETAPTS = 40;
// potential plot data
const int x09::PPERIMETERPTS = 100;
const int x09::PRPTS = 40;
const int x09::PTHETAPTS = 64;
const int x09::PNLEVEL = 20;
PLFLT x09:: clevel[] = { -1., -.8, -.6, -.4, -.2, 0, .2, .4, .6, .8, 1. };
// Transformation function
//const PLFLT x09::tr[] = {XSPA, 0.0, -1.0, 0.0, YSPA, -1.0};
static const PLFLT tr[] = { x09::XSPA, 0.0, -1.0, 0.0, x09::YSPA, -1.0 };
static void mypltr( PLFLT x, PLFLT y, PLFLT *tx, PLFLT *ty, void * /* pltr_data */ )
{
*tx = tr[0] * x + tr[1] * y + tr[2];
*ty = tr[3] * x + tr[4] * y + tr[5];
}
// Does a large series of unlabelled and labelled contour plots.
x09::x09( int argc, const char **argv )
{
int i, j;
PLFLT *xg1 = new PLFLT[XPTS];
PLFLT *yg1 = new PLFLT[YPTS];
PLcGrid cgrid1;
PLcGrid2 cgrid2;
PLFLT **z;
PLFLT **w;
PLFLT xx, yy, argx, argy, distort;
static PLINT mark = 1500;
static PLINT space = 1500;
pls = new plstream();
// Parse and process command line arguments.
pls->parseopts( &argc, argv, PL_PARSE_FULL );
// Initialize plplot
pls->init();
pls->Alloc2dGrid( &z, XPTS, YPTS );
pls->Alloc2dGrid( &w, XPTS, YPTS );
// Set up function arrays
for ( i = 0; i < XPTS; i++ )
{
xx = (PLFLT) ( i - ( XPTS / 2 ) ) / (PLFLT) ( XPTS / 2 );
for ( j = 0; j < YPTS; j++ )
{
yy = (PLFLT) ( j - ( YPTS / 2 ) ) / (PLFLT) ( YPTS / 2 ) - 1.0;
z[i][j] = xx * xx - yy * yy;
w[i][j] = 2 * xx * yy;
}
}
// Set up grids
cgrid1.xg = xg1;
cgrid1.yg = yg1;
cgrid1.nx = XPTS;
cgrid1.ny = YPTS;
pls->Alloc2dGrid( &cgrid2.xg, XPTS, YPTS );
pls->Alloc2dGrid( &cgrid2.yg, XPTS, YPTS );
cgrid2.nx = XPTS;
cgrid2.ny = YPTS;
for ( i = 0; i < XPTS; i++ )
{
for ( j = 0; j < YPTS; j++ )
{
mypltr( (PLFLT) i, (PLFLT) j, &xx, &yy, NULL );
argx = xx * M_PI / 2;
argy = yy * M_PI / 2;
distort = 0.4;
cgrid1.xg[i] = xx + distort * cos( argx );
cgrid1.yg[j] = yy - distort * cos( argy );
cgrid2.xg[i][j] = xx + distort * cos( argx ) * cos( argy );
cgrid2.yg[i][j] = yy - distort * cos( argx ) * cos( argy );
}
}
// Plot using scaled identity transform used to create xg0 and yg0
// pls->_setcontlabelparam(0.006, 0.3, 0.1, 0);
// pls->env(-1.0, 1.0, -1.0, 1.0, 0, 0);
// pls->col0(2);
// pls->cont( z, XPTS, YPTS, 1, XPTS, 1, YPTS, clevel, 11, mypltr, NULL );
// pls->styl(1, &mark, &space);
// pls->col0(3);
// pls->cont(w, XPTS, YPTS, 1, XPTS, 1, YPTS, clevel, 11, mypltr, NULL );
// pls->styl(0, &mark, &space);
// pls->col0(1);
// pls->lab("X Coordinate", "Y Coordinate", "Streamlines of flow");
//
pls->setcontlabelformat( 4, 3 );
pls->setcontlabelparam( 0.006, 0.3, 0.1, 1 );
pls->env( -1.0, 1.0, -1.0, 1.0, 0, 0 );
pls->col0( 2 );
pls->cont( z, XPTS, YPTS, 1, XPTS, 1, YPTS, clevel, 11, mypltr, NULL );
pls->styl( 1, &mark, &space );
pls->col0( 3 );
pls->cont( w, XPTS, YPTS, 1, XPTS, 1, YPTS, clevel, 11, mypltr, NULL );
pls->styl( 0, &mark, &space );
pls->col0( 1 );
pls->lab( "X Coordinate", "Y Coordinate", "Streamlines of flow" );
pls->setcontlabelparam( 0.006, 0.3, 0.1, 0 );
// Plot using 1d coordinate transform
pls->env( -1.0, 1.0, -1.0, 1.0, 0, 0 );
pls->col0( 2 );
pls->cont( z, XPTS, YPTS, 1, XPTS, 1, YPTS, clevel, 11,
plstream::tr1, (void *) &cgrid1 );
pls->styl( 1, &mark, &space );
pls->col0( 3 );
pls->cont( w, XPTS, YPTS, 1, XPTS, 1, YPTS, clevel, 11,
plstream::tr1, (void *) &cgrid1 );
pls->styl( 0, NULL, NULL );
pls->col0( 1 );
pls->lab( "X Coordinate", "Y Coordinate", "Streamlines of flow" );
// pls->_setcontlabelparam(0.006, 0.3, 0.1, 1);
// pls->env(-1.0, 1.0, -1.0, 1.0, 0, 0);
// pls->col0(2);
// pls->cont(z, XPTS, YPTS, 1, XPTS, 1, YPTS, clevel, 11,
// pltr1, (void *) &cgrid1 );
// pls->styl(2, &mark, &space);
// pls->col0(3);
// pls->cont(w, XPTS, YPTS, 1, XPTS, 1, YPTS, clevel, 11,
// pltr1, (void *) &cgrid1 );
// pls->styl(0, &mark, &space);
// pls->col0(1);
// pls->lab("X Coordinate", "Y Coordinate", "Streamlines of flow");
// pls->_setcontlabelparam(0.006, 0.3, 0.1, 0);
//
// Plot using 2d coordinate transform
pls->env( -1.0, 1.0, -1.0, 1.0, 0, 0 );
pls->col0( 2 );
pls->cont( z, XPTS, YPTS, 1, XPTS, 1, YPTS, clevel, 11,
plstream::tr2, (void *) &cgrid2 );
pls->styl( 1, &mark, &space );
pls->col0( 3 );
pls->cont( w, XPTS, YPTS, 1, XPTS, 1, YPTS, clevel, 11,
plstream::tr2, (void *) &cgrid2 );
pls->styl( 0, &mark, &space );
pls->col0( 1 );
pls->lab( "X Coordinate", "Y Coordinate", "Streamlines of flow" );
// pls->_setcontlabelparam(0.006, 0.3, 0.1, 1);
// pls->env(-1.0, 1.0, -1.0, 1.0, 0, 0);
// pls->col0(2);
// pls->cont(z, XPTS, YPTS, 1, XPTS, 1, YPTS, clevel, 11,
// pltr2, (void *) &cgrid2 );
// pls->styl(1, &mark, &space);
// pls->col0(3);
// pls->cont(w, XPTS, YPTS, 1, XPTS, 1, YPTS, clevel, 11,
// pltr2, (void *) &cgrid2 );
// pls->styl(1, &mark0, &space0);
// pls->col0(1);
// pls->lab("X Coordinate", "Y Coordinate", "Streamlines of flow");
//
pls->setcontlabelparam( 0.006, 0.3, 0.1, 0 );
polar();
//
// pls->setcontlabelparam(0.006, 0.3, 0.1, 1);
// polar();
//
pls->setcontlabelparam( 0.006, 0.3, 0.1, 0 );
potential();
//
// pls->setcontlabelparam(0.006, 0.3, 0.1, 1);
// potential();
//
// pls->end();
pls->Free2dGrid( cgrid2.xg, XPTS, YPTS );
pls->Free2dGrid( cgrid2.yg, XPTS, YPTS );
pls->Free2dGrid( z, XPTS, YPTS );
pls->Free2dGrid( w, XPTS, YPTS );
delete pls;
delete[] yg1;
delete[] xg1;
}
void x09::polar()
// polar contour plot example.
{
int i, j;
PLFLT *px = new PLFLT[PERIMETERPTS];
PLFLT *py = new PLFLT[PERIMETERPTS];
PLcGrid2 cgrid2;
PLFLT **z;
PLFLT t, r, theta;
PLFLT *lev = new PLFLT[10];
pls->Alloc2dGrid( &cgrid2.xg, RPTS, THETAPTS );
pls->Alloc2dGrid( &cgrid2.yg, RPTS, THETAPTS );
pls->Alloc2dGrid( &z, RPTS, THETAPTS );
cgrid2.nx = RPTS;
cgrid2.ny = THETAPTS;
pls->env( -1., 1., -1., 1., 0, -2 );
pls->col0( 1 );
// Perimeter
for ( i = 0; i < PERIMETERPTS; i++ )
{
t = ( 2. * M_PI / ( PERIMETERPTS - 1 ) ) * (PLFLT) i;
px[i] = cos( t );
py[i] = sin( t );
}
pls->line( PERIMETERPTS, px, py );
// Create data to be contoured.
for ( i = 0; i < RPTS; i++ )
{
r = i / (PLFLT) ( RPTS - 1 );
for ( j = 0; j < THETAPTS; j++ )
{
theta = ( 2. * M_PI / (PLFLT) ( THETAPTS - 1 ) ) * (PLFLT) j;
cgrid2.xg[i][j] = r * cos( theta );
cgrid2.yg[i][j] = r * sin( theta );
z[i][j] = r;
}
}
for ( i = 0; i < 10; i++ )
{
lev[i] = 0.05 + 0.10 * (PLFLT) i;
}
pls->col0( 2 );
pls->cont( z, RPTS, THETAPTS, 1, RPTS, 1, THETAPTS, lev, 10,
plstream::tr2, (void *) &cgrid2 );
pls->col0( 1 );
pls->lab( "", "", "Polar Contour Plot" );
pls->Free2dGrid( cgrid2.xg, RPTS, THETAPTS );
pls->Free2dGrid( cgrid2.yg, RPTS, THETAPTS );
pls->Free2dGrid( z, RPTS, THETAPTS );
delete[] px;
delete[] py;
delete[] lev;
}
void x09::potential()
// Shielded potential contour plot example.
{
int i, j;
PLFLT rmax, xmin, xmax, x0, ymin, ymax, y0, zmin, zmax;
PLFLT peps, xpmin, xpmax, ypmin, ypmax;
PLFLT eps, q1, d1, q1i, d1i, q2, d2, q2i, d2i;
PLFLT div1, div1i, div2, div2i;
PLcGrid2 cgrid2;
PLFLT **z;
int nlevelneg, nlevelpos;
PLFLT dz, clevel;
PLFLT *clevelneg = new PLFLT[PNLEVEL];
PLFLT *clevelpos = new PLFLT[PNLEVEL];
int ncollin, ncolbox, ncollab;
PLFLT *px = new PLFLT[PPERIMETERPTS];
PLFLT *py = new PLFLT[PPERIMETERPTS];
PLFLT t, r, theta;
// Create data to be contoured.
pls->Alloc2dGrid( &cgrid2.xg, PRPTS, PTHETAPTS );
pls->Alloc2dGrid( &cgrid2.yg, PRPTS, PTHETAPTS );
pls->Alloc2dGrid( &z, PRPTS, PTHETAPTS );
cgrid2.nx = PRPTS;
cgrid2.ny = PTHETAPTS;
// r = 0.;
for ( i = 0; i < PRPTS; i++ )
{
r = 0.5 + (PLFLT) i;
for ( j = 0; j < PTHETAPTS; j++ )
{
theta = ( 2. * M_PI / (PLFLT) ( PTHETAPTS - 1 ) ) * ( 0.5 + (PLFLT) j );
cgrid2.xg[i][j] = r * cos( theta );
cgrid2.yg[i][j] = r * sin( theta );
}
}
rmax = r;
pls->MinMax2dGrid( cgrid2.xg, PRPTS, PTHETAPTS, &xmax, &xmin );
pls->MinMax2dGrid( cgrid2.yg, PRPTS, PTHETAPTS, &ymax, &ymin );
x0 = ( xmin + xmax ) / 2.;
y0 = ( ymin + ymax ) / 2.;
// Expanded limits
peps = 0.05;
xpmin = xmin - fabs( xmin ) * peps;
xpmax = xmax + fabs( xmax ) * peps;
ypmin = ymin - fabs( ymin ) * peps;
ypmax = ymax + fabs( ymax ) * peps;
// Potential inside a conducting cylinder (or sphere) by method of images.
// Charge 1 is placed at (d1, d1), with image charge at (d2, d2).
// Charge 2 is placed at (d1, -d1), with image charge at (d2, -d2).
// Also put in smoothing term at small distances.
eps = 2.;
q1 = 1.;
d1 = rmax / 4.;
q1i = -q1 * rmax / d1;
d1i = pow( rmax, 2 ) / d1;
q2 = -1.;
d2 = rmax / 4.;
q2i = -q2 * rmax / d2;
d2i = pow( rmax, 2 ) / d2;
for ( i = 0; i < PRPTS; i++ )
{
for ( j = 0; j < PTHETAPTS; j++ )
{
div1 = sqrt( pow( cgrid2.xg[i][j] - d1, 2 ) + pow( cgrid2.yg[i][j] - d1, 2 ) + pow( eps, 2 ) );
div1i = sqrt( pow( cgrid2.xg[i][j] - d1i, 2 ) + pow( cgrid2.yg[i][j] - d1i, 2 ) + pow( eps, 2 ) );
div2 = sqrt( pow( cgrid2.xg[i][j] - d2, 2 ) + pow( cgrid2.yg[i][j] + d2, 2 ) + pow( eps, 2 ) );
div2i = sqrt( pow( cgrid2.xg[i][j] - d2i, 2 ) + pow( cgrid2.yg[i][j] + d2i, 2 ) + pow( eps, 2 ) );
z[i][j] = q1 / div1 + q1i / div1i + q2 / div2 + q2i / div2i;
}
}
pls->MinMax2dGrid( z, PRPTS, PTHETAPTS, &zmax, &zmin );
// printf("%.15g %.15g %.15g %.15g %.15g %.15g %.15g %.15g \n",
// q1, d1, q1i, d1i, q2, d2, q2i, d2i);
// printf("%.15g %.15g %.15g %.15g %.15g %.15g\n",
// xmin,xmax,ymin,ymax,zmin,zmax);
// Positive and negative contour levels.
dz = ( zmax - zmin ) / (PLFLT) PNLEVEL;
nlevelneg = 0;
nlevelpos = 0;
for ( i = 0; i < PNLEVEL; i++ )
{
clevel = zmin + ( (PLFLT) i + 0.5 ) * dz;
if ( clevel <= 0. )
clevelneg[nlevelneg++] = clevel;
else
clevelpos[nlevelpos++] = clevel;
}
// Colours!
ncollin = 11;
ncolbox = 1;
ncollab = 2;
// Finally start plotting this page!
pls->adv( 0 );
pls->col0( ncolbox );
pls->vpas( 0.1, 0.9, 0.1, 0.9, 1.0 );
pls->wind( xpmin, xpmax, ypmin, ypmax );
pls->box( "", 0., 0, "", 0., 0 );
pls->col0( ncollin );
if ( nlevelneg > 0 )
{
// Negative contours
pls->lsty( 2 );
pls->cont( z, PRPTS, PTHETAPTS, 1, PRPTS, 1, PTHETAPTS,
clevelneg, nlevelneg, plstream::tr2, (void *) &cgrid2 );
}
if ( nlevelpos > 0 )
{
// Positive contours
pls->lsty( 1 );
pls->cont( z, PRPTS, PTHETAPTS, 1, PRPTS, 1, PTHETAPTS,
clevelpos, nlevelpos, plstream::tr2, (void *) &cgrid2 );
}
// Draw outer boundary
for ( i = 0; i < PPERIMETERPTS; i++ )
{
t = ( 2. * M_PI / ( PPERIMETERPTS - 1 ) ) * (PLFLT) i;
px[i] = x0 + rmax*cos( t );
py[i] = y0 + rmax*sin( t );
}
pls->col0( ncolbox );
pls->line( PPERIMETERPTS, px, py );
pls->col0( ncollab );
pls->lab( "", "", "Shielded potential of charges in a conducting sphere" );
pls->Free2dGrid( cgrid2.xg, RPTS, THETAPTS );
pls->Free2dGrid( cgrid2.yg, RPTS, THETAPTS );
pls->Free2dGrid( z, RPTS, THETAPTS );
delete[] clevelneg;
delete[] clevelpos;
delete[] px;
delete[] py;
}
int main( int argc, const char **argv )
{
x09 *x = new x09( argc, argv );
delete x;
}
//--------------------------------------------------------------------------
// End of x09.cc
//--------------------------------------------------------------------------
|