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t/x08.pl  view on Meta::CPAN

my $z;
if ($rosen) {
  $z = (1 - $xx) ** 2 + 100 * ($yy - ($xx ** 2)) ** 2;
  # The log argument may be zero for just the right grid.
  $z = log ($z);
} else {
  my $r = sqrt ($xx * $xx + $yy * $yy);
  $z = exp (-$r * $r) * cos (2.0 * pi * $r);
}
$z->inplace->setnonfinitetobad;
$z->inplace->setbadtoval(-5); # -MAXFLOAT would mess-up up the scale

my (@indexymin, @indexymax);
my $square_root = sqrt(1. - hclip(( (sequence(XPTS) - $x0) / $a ) ** 2, 1));
# Add 0.5 to find nearest integer and therefore preserve symmetry
# with regard to lower and upper bound of y range.
my $indexymin = lclip( 0.5 + $y0 - $b * $square_root, 0 )->indx;
# indexymax calculated with the convention that it is 1
# greater than highest valid index.
my $indexymax = hclip( 1 + ( 0.5 + $y0 + $b * $square_root ), YPTS )->indx;
my $zlimited = zeroes (XPTS, YPTS);
for my $i ( $indexxmin..$indexxmax-1 ) {
  my $j = [ $indexymin->at($i), $indexymax->at($i) ];
  $zlimited->index($i)->slice($j) .= $z->index($i)->slice($j);
}

my ($zmin, $zmax) = (min($z), max($z));
my $nlevel = LEVELS;
my $step = ($zmax - $zmin) / ($nlevel + 1);
my $clevel = $zmin + $step + $step * sequence ($nlevel);

pllightsource (1., 1., 1.);

for (my $k = 0; $k < 2; $k++) {
  for (my $ifshade = 0; $ifshade < 5; $ifshade++) {
    pladv (0);
    plvpor (0.0, 1.0, 0.0, 0.9);
    plwind (-1.0, 1.0, -0.9, 1.1);
    plcol0 (3);
    plmtex (1.0, 0.5, 0.5, "t", $title[$k]);
    plcol0(1);
    if ($rosen) {
      plw3d (1.0, 1.0, 1.0, -1.5, 1.5, -0.5, 1.5, $zmin, $zmax,
             $alt[$k], $az[$k]);
    } else {
      plw3d (1.0, 1.0, 1.0, -1.0, 1.0, -1.0, 1.0, $zmin, $zmax,
             $alt[$k], $az[$k]);
    }

    plbox3 (0.0, 0, 0.0, 0, 0.0, 0,
            "bnstu", "x axis", "bnstu", "y axis", "bcdmnstuv", "z axis");
    plcol0 (2);

    cmap1_init(($ifshade == 0) || 0);
    if ($ifshade == 0) {        # diffuse light surface plot
      plsurf3d($x, $y, $z, 0, pdl []);
    } elsif ($ifshade == 1) { # magnitude colored plot
      plsurf3d($x, $y, $z, MAG_COLOR, pdl []);
    }
    elsif ($ifshade == 2) {     # magnitude colored plot with faceted squares
      plsurf3d($x, $y, $z, MAG_COLOR | FACETED, pdl []);
    } elsif ($ifshade == 3) {   # magnitude colored plot with contours
      plsurf3d($x, $y, $z, MAG_COLOR | SURF_CONT | BASE_CONT, $clevel);
    } else {          # magnitude colored plot with contours and index limits.
      plsurf3dl(
        $x, $y, $zlimited, MAG_COLOR | SURF_CONT | BASE_CONT, $clevel,
        $indexxmin, $indexxmax, $indexymin, $indexymax,
      );
    }
  }
}

plend ();