static void polar( void )
//polar contour plot example.
{
int i, j;
PLcGrid2 cgrid2;
PLFLT **z;
PLFLT px[PERIMETERPTS], py[PERIMETERPTS];
PLFLT t, r, theta;
PLFLT lev[10];
plenv( -1., 1., -1., 1., 0, -2 );
plcol0( 1 );
//Perimeter
for ( i = 0; i < PERIMETERPTS; i++ )
{
t = ( 2. * M_PI / ( PERIMETERPTS - 1 ) ) * (double) i;
px[i] = cos( t );
py[i] = sin( t );
}
plline( PERIMETERPTS, px, py );
//create data to be contoured.
plAlloc2dGrid( &cgrid2.xg, RPTS, THETAPTS );
plAlloc2dGrid( &cgrid2.yg, RPTS, THETAPTS );
plAlloc2dGrid( &z, RPTS, THETAPTS );
cgrid2.nx = RPTS;
cgrid2.ny = THETAPTS;
for ( i = 0; i < RPTS; i++ )
{
r = i / (double) ( RPTS - 1 );
for ( j = 0; j < THETAPTS; j++ )
{
theta = ( 2. * M_PI / (double) ( THETAPTS - 1 ) ) * (double) 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 * (double) i;
}
plcol0( 2 );
plcont( (const PLFLT * const *) z, RPTS, THETAPTS, 1, RPTS, 1, THETAPTS, lev, 10,
pltr2, (void *) &cgrid2 );
plcol0( 1 );
pllab( "", "", "Polar Contour Plot" );
plFree2dGrid( z, RPTS, THETAPTS );
plFree2dGrid( cgrid2.xg, RPTS, THETAPTS );
plFree2dGrid( cgrid2.yg, RPTS, THETAPTS );
}
void
plot5(void)
{
int i, j;
PLFLT xx, yy;
PLFLT **z, **w;
static PLINT mark = 1500, space = 1500;
/* Set up function arrays */
plAlloc2dGrid(&z, XPTS, YPTS);
plAlloc2dGrid(&w, XPTS, YPTS);
for (i = 0; i < XPTS; i++) {
xx = (double) (i - (XPTS / 2)) / (double) (XPTS / 2);
for (j = 0; j < YPTS; j++) {
yy = (double) (j - (YPTS / 2)) / (double) (YPTS / 2) - 1.0;
z[i][j] = xx * xx - yy * yy;
w[i][j] = 2 * xx * yy;
}
}
plenv(-1.0, 1.0, -1.0, 1.0, 0, 0);
plcol0(2);
plcont(z, XPTS, YPTS, 1, XPTS, 1, YPTS, clevel, 11, mypltr, NULL);
plstyl(1, &mark, &space);
plcol0(3);
plcont(w, XPTS, YPTS, 1, XPTS, 1, YPTS, clevel, 11, mypltr, NULL);
plcol0(1);
pllab("X Coordinate", "Y Coordinate", "Streamlines of flow");
plflush();
/* Clean up */
plFree2dGrid(z, XPTS, YPTS);
plFree2dGrid(w, XPTS, YPTS);
}
void
cont_store(PLFLT **f, PLINT nx, PLINT ny, PLINT kx, PLINT lx,
PLINT ky, PLINT ly, PLFLT *clevel, PLINT nlevel,
void (*pltr) (PLFLT, PLFLT, PLFLT *, PLFLT *, PLPointer),
PLPointer pltr_data,
CONT_LEVEL **contour)
{
cont3d = 1;
plcont(f, nx, ny, kx, lx, ky, ly, clevel, nlevel,
pltr, pltr_data);
*contour = startlev;
cont3d = 0;
}
void
cont_store(PLFLT *x, PLFLT *y, PLFLT **z, PLINT nx, PLINT ny, PLINT kx, PLINT lx,
PLINT ky, PLINT ly, PLFLT *clevel, PLINT nlevel, CONT_LEVEL **contour)
{
PLcGrid grid1;
cont3d = 1;
grid1.nx = nx; grid1.ny = ny; grid1.xg = x; grid1.yg = y;
plcont(z, nx, ny, 1, nx, 1, ny, clevel, nlevel,
pltr1, (void *) & grid1 );
*contour = startlev;
cont3d = 0;
}
MZ_DLLEXPORT
void c_plshades( PLFLT **a, PLINT nx, PLINT ny, PLINT (*defined) (PLFLT, PLFLT),
PLFLT xmin, PLFLT xmax, PLFLT ymin, PLFLT ymax,
PLFLT *clevel, PLINT nlevel, PLINT fill_width,
PLINT cont_color, PLINT cont_width,
void (*fill) (PLINT, PLFLT *, PLFLT *), PLINT rectangular,
void (*pltr) (PLFLT, PLFLT, PLFLT *, PLFLT *, PLPointer),
PLPointer pltr_data )
{
PLFLT shade_min, shade_max, shade_color;
PLINT i, init_color, init_width;
for (i = 0; i < nlevel-1; i++) {
shade_min = clevel[i];
shade_max = clevel[i+1];
shade_color = i / (PLFLT) (nlevel-2);
/* The constants in order mean
* (1) color map1,
* (0, 0, 0, 0) all edge effects will be done with plcont rather
* than the normal plshade drawing which gets partially blocked
* when sequential shading is done as in the present case */
plshade(a, nx, ny, defined, xmin, xmax, ymin, ymax,
shade_min, shade_max,
1, shade_color, fill_width,
0, 0, 0, 0,
fill, rectangular, pltr, pltr_data);
}
if(cont_color > 0 && cont_width > 0) {
init_color = plsc->icol0;
init_width = plsc->width;
plcol0(cont_color);
plwid(cont_width);
plcont(a, nx, ny, 1, nx, 1, ny, clevel, nlevel, pltr, pltr_data);
plcol0(init_color);
plwid(init_width);
}
}
int
main( int argc, const char *argv[] )
{
int i, j;
PLFLT xx, yy, argx, argy, distort;
static PLINT mark = 1500, space = 1500;
PLFLT **z, **w;
PLFLT xg1[XPTS], yg1[YPTS];
PLcGrid cgrid1;
PLcGrid2 cgrid2;
// Parse and process command line arguments
(void) plparseopts( &argc, argv, PL_PARSE_FULL );
// Initialize plplot
plinit();
// Set up function arrays
plAlloc2dGrid( &z, XPTS, YPTS );
plAlloc2dGrid( &w, XPTS, YPTS );
for ( i = 0; i < XPTS; i++ )
{
xx = (double) ( i - ( XPTS / 2 ) ) / (double) ( XPTS / 2 );
for ( j = 0; j < YPTS; j++ )
{
yy = (double) ( j - ( YPTS / 2 ) ) / (double) ( 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;
plAlloc2dGrid( &cgrid2.xg, XPTS, YPTS );
plAlloc2dGrid( &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 identity transform
//
// plenv(-1.0, 1.0, -1.0, 1.0, 0, 0);
// plcol0(2);
// plcont(z, XPTS, YPTS, 1, XPTS, 1, YPTS, clevel, 11, mypltr, NULL);
// plstyl(1, &mark, &space);
// plcol0(3);
// plcont(w, XPTS, YPTS, 1, XPTS, 1, YPTS, clevel, 11, mypltr, NULL);
// plstyl(0, &mark, &space);
// plcol0(1);
// pllab("X Coordinate", "Y Coordinate", "Streamlines of flow");
//
pl_setcontlabelformat( 4, 3 );
pl_setcontlabelparam( 0.006, 0.3, 0.1, 1 );
plenv( -1.0, 1.0, -1.0, 1.0, 0, 0 );
plcol0( 2 );
plcont( (const PLFLT * const *) z, XPTS, YPTS, 1, XPTS, 1, YPTS, clevel, 11, mypltr, NULL );
plstyl( 1, &mark, &space );
plcol0( 3 );
plcont( (const PLFLT * const *) w, XPTS, YPTS, 1, XPTS, 1, YPTS, clevel, 11, mypltr, NULL );
plstyl( 0, &mark, &space );
plcol0( 1 );
pllab( "X Coordinate", "Y Coordinate", "Streamlines of flow" );
pl_setcontlabelparam( 0.006, 0.3, 0.1, 0 );
// Plot using 1d coordinate transform
plenv( -1.0, 1.0, -1.0, 1.0, 0, 0 );
plcol0( 2 );
plcont( (const PLFLT * const *) z, XPTS, YPTS, 1, XPTS, 1, YPTS, clevel, 11,
pltr1, (void *) &cgrid1 );
plstyl( 1, &mark, &space );
plcol0( 3 );
plcont( (const PLFLT * const *) w, XPTS, YPTS, 1, XPTS, 1, YPTS, clevel, 11,
pltr1, (void *) &cgrid1 );
plstyl( 0, &mark, &space );
plcol0( 1 );
pllab( "X Coordinate", "Y Coordinate", "Streamlines of flow" );
//
// pl_setcontlabelparam(0.006, 0.3, 0.1, 1);
// plenv(-1.0, 1.0, -1.0, 1.0, 0, 0);
// plcol0(2);
// plcont((const PLFLT **) z, XPTS, YPTS, 1, XPTS, 1, YPTS, clevel, 11,
// pltr1, (void *) &cgrid1);
//
// plstyl(1, &mark, &space);
// plcol0(3);
// plcont((const PLFLT **) w, XPTS, YPTS, 1, XPTS, 1, YPTS, clevel, 11,
// pltr1, (void *) &cgrid1);
// plstyl(0, &mark, &space);
// plcol0(1);
// pllab("X Coordinate", "Y Coordinate", "Streamlines of flow");
// pl_setcontlabelparam(0.006, 0.3, 0.1, 0);
//
// Plot using 2d coordinate transform
plenv( -1.0, 1.0, -1.0, 1.0, 0, 0 );
plcol0( 2 );
plcont( (const PLFLT * const *) z, XPTS, YPTS, 1, XPTS, 1, YPTS, clevel, 11,
pltr2, (void *) &cgrid2 );
plstyl( 1, &mark, &space );
plcol0( 3 );
plcont( (const PLFLT * const *) w, XPTS, YPTS, 1, XPTS, 1, YPTS, clevel, 11,
pltr2, (void *) &cgrid2 );
plstyl( 0, &mark, &space );
plcol0( 1 );
pllab( "X Coordinate", "Y Coordinate", "Streamlines of flow" );
//
// pl_setcontlabelparam(0.006, 0.3, 0.1, 1);
// plenv(-1.0, 1.0, -1.0, 1.0, 0, 0);
// plcol0(2);
// plcont((const PLFLT **) z, XPTS, YPTS, 1, XPTS, 1, YPTS, clevel, 11,
// pltr2, (void *) &cgrid2);
//
// plstyl(1, &mark, &space);
// plcol0(3);
// plcont((const PLFLT **) w, XPTS, YPTS, 1, XPTS, 1, YPTS, clevel, 11,
// pltr2, (void *) &cgrid2);
// plstyl(0, &mark, &space);
// plcol0(1);
// pllab("X Coordinate", "Y Coordinate", "Streamlines of flow");
//
pl_setcontlabelparam( 0.006, 0.3, 0.1, 0 );
polar();
//
// pl_setcontlabelparam(0.006, 0.3, 0.1, 1);
// polar();
//
pl_setcontlabelparam( 0.006, 0.3, 0.1, 0 );
potential();
//
// pl_setcontlabelparam(0.006, 0.3, 0.1, 1);
// potential();
//
// Clean up
plFree2dGrid( z, XPTS, YPTS );
plFree2dGrid( w, XPTS, YPTS );
plFree2dGrid( cgrid2.xg, XPTS, YPTS );
plFree2dGrid( cgrid2.yg, XPTS, YPTS );
plend();
exit( 0 );
}
static void potential( void )
//shielded potential contour plot example.
{
int i, j;
PLcGrid2 cgrid2;
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;
PLFLT **z;
PLINT nlevelneg, nlevelpos;
PLFLT dz, clevel2, clevelneg[PNLEVEL], clevelpos[PNLEVEL];
PLINT ncollin, ncolbox, ncollab;
PLFLT px[PPERIMETERPTS], py[PPERIMETERPTS];
PLFLT t, r, theta;
//create data to be contoured.
plAlloc2dGrid( &cgrid2.xg, PRPTS, PTHETAPTS );
plAlloc2dGrid( &cgrid2.yg, PRPTS, PTHETAPTS );
plAlloc2dGrid( &z, PRPTS, PTHETAPTS );
cgrid2.nx = PRPTS;
cgrid2.ny = PTHETAPTS;
for ( i = 0; i < PRPTS; i++ )
{
r = 0.5 + (double) i;
for ( j = 0; j < PTHETAPTS; j++ )
{
theta = ( 2. * M_PI / (double) ( PTHETAPTS - 1 ) ) * ( 0.5 + (double) j );
cgrid2.xg[i][j] = r * cos( theta );
cgrid2.yg[i][j] = r * sin( theta );
}
}
rmax = r;
f2mnmx( cgrid2.xg, PRPTS, PTHETAPTS, &xmin, &xmax );
f2mnmx( cgrid2.yg, PRPTS, PTHETAPTS, &ymin, &ymax );
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;
}
}
f2mnmx( z, PRPTS, PTHETAPTS, &zmin, &zmax );
// 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 ) / (double) PNLEVEL;
nlevelneg = 0;
nlevelpos = 0;
for ( i = 0; i < PNLEVEL; i++ )
{
clevel2 = zmin + ( (double) i + 0.5 ) * dz;
if ( clevel2 <= 0. )
clevelneg[nlevelneg++] = clevel2;
else
clevelpos[nlevelpos++] = clevel2;
}
// Colours!
ncollin = 11;
ncolbox = 1;
ncollab = 2;
// Finally start plotting this page!
pladv( 0 );
plcol0( ncolbox );
plvpas( 0.1, 0.9, 0.1, 0.9, 1.0 );
plwind( xpmin, xpmax, ypmin, ypmax );
plbox( "", 0., 0, "", 0., 0 );
plcol0( ncollin );
if ( nlevelneg > 0 )
{
// Negative contours
pllsty( 2 );
plcont( (const PLFLT * const *) z, PRPTS, PTHETAPTS, 1, PRPTS, 1, PTHETAPTS,
clevelneg, nlevelneg, pltr2, (void *) &cgrid2 );
}
if ( nlevelpos > 0 )
{
// Positive contours
pllsty( 1 );
plcont( (const PLFLT * const *) z, PRPTS, PTHETAPTS, 1, PRPTS, 1, PTHETAPTS,
clevelpos, nlevelpos, pltr2, (void *) &cgrid2 );
}
// Draw outer boundary
for ( i = 0; i < PPERIMETERPTS; i++ )
{
t = ( 2. * M_PI / ( PPERIMETERPTS - 1 ) ) * (double) i;
px[i] = x0 + rmax * cos( t );
py[i] = y0 + rmax * sin( t );
}
plcol0( ncolbox );
plline( PPERIMETERPTS, px, py );
plcol0( ncollab );
pllab( "", "", "Shielded potential of charges in a conducting sphere" );
plFree2dGrid( z, PRPTS, PTHETAPTS );
plFree2dGrid( cgrid2.xg, PRPTS, PTHETAPTS );
plFree2dGrid( cgrid2.yg, PRPTS, PTHETAPTS );
}