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View of /branches/vis12/test/hlic/hlic.diderot

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Revision 1753 - (download) (annotate)
Wed Mar 21 07:35:36 2012 UTC (7 years, 7 months ago) by glk
File size: 1280 byte(s)
fix suggested by JHR
// BUG:
// output is different with different runs, in a seemingly non-deterministic way
// to test: do "./hlic && unu minmax out.nrrd" about 20 times

int imgSize = 200;
real h = 0.25;    // step size of integration
int stepNum = 5; // take this many steps both upstream and downstream

field#1(2)[2] V = load("tor2slice-vec0.nrrd") ⊛ ctmr;
field#0(2)[] R = load("tor2slice-rand.nrrd") ⊛ tent;

strand LIC (int xi, int yi) {
    real xx = lerp(0.0, 79.0, -0.5, real(xi), real(imgSize)-0.5);
    real yy = lerp(0.0, 79.0, -0.5, real(yi), real(imgSize)-0.5);
    vec2 pos0 = [xx,yy];
    vec2 pos0backup = [xx,yy];
    vec2 pos = pos0;
    vec2 step = [0.0,0.0];
    output vec3 out = [0.0,0.0,0.0];
    real sum = 0.0;
    int num = 0;
    real dir = 1.0;
    int mon = 0;

    update {
      mon += 1;
      step = h*dir*V(pos);
      if (inside(pos + step, V) && inside(pos + step, R)) {
        pos += step;
      }
      if (num == stepNum && dir > 0.0) {
        num = 0;
        pos = pos0backup;
        dir = -1.0;
      }
      if (num == stepNum && dir < 0.0) {
        stabilize;
      }
      sum += R(pos);
      num += 1;
    }

    stabilize {
      out = [pos[0], pos[1], sum];
    }
}

initially [ LIC(xi, yi) | yi in 0..(imgSize-1), xi in 0..(imgSize-1) ];

root@smlnj-gforge.cs.uchicago.edu
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