Annotation of /benchmarks/programs/ridge3d/bmark-diderot.diderot

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Revision 1582 - (view) (download)

1 :	glk	1582
2 :			int gridSize = 120;
3 :			field#2(3)[] F = bspln3 ⊛ load("../../data/lungcrop.nrrd");
4 :			input int stepsMax = 20;
5 :			input real epsilon = 0.005;
6 :			real travelMax = 5.0;
7 :
8 :			strand sample (int ui, int vi, int wi) {
9 :			output vec3 pos = [lerp(21.6401, 21.6401 + 140.0*0.5,
10 :			-0.5, real(ui), real(gridSize)-0.5),
11 :			lerp(-175.8792, -175.8792 + 200.0*0.5,
12 :			-0.5, real(vi), real(gridSize)-0.5),
13 :			lerp(-188.0000, -188.0000 + 140.0*0.5,
14 :			-0.5, real(wi), real(gridSize)-0.5)];
15 :			int steps = 0;
16 :			real travel = 0.0;
17 :			update {
18 :			if (!inside(pos, F) || steps > stepsMax || travel > travelMax) {
19 :			die;
20 :			}
21 :			real gmag = |∇F(pos)|;
22 :			if (gmag == 0.0) { // can't compute step if |∇F|, so have to bail
23 :			die;
24 :			}
25 :			vec3 grad = ∇F(pos);
26 :			tensor[3,3] hess = ∇⊗∇F(pos);
27 :
28 :
29 :			real{3} eval = evals(hess);
30 :			real strn = -eval{2};
31 :			vec3{3} evec = evecs(hess);
32 :			vec3 dir = normalize((evec{2}⊗evec{2} + evec{1}⊗evec{1})•grad);
33 :			/*
34 :			vec3 dir = normalize(grad);
35 :			real strn = 0.0;
36 :			*/
37 :
38 :			real fdd = grad•dir;
39 :			real sdd = dir•hess•dir;
40 :			vec3 delta = (0.1 if sdd >= 0.0 else -fdd/sdd)*dir;
41 :			if (|delta| < epsilon) {
42 :			if (strn >= 300.0) {
43 :			stabilize;
44 :			}
45 :			die;
46 :			}
47 :			// BUG: can't have: else {
48 :			pos += delta;
49 :			steps += 1;
50 :			travel += |delta|;
51 :			// BUG: can't have: }
52 :			}
53 :			}
54 :
55 :			initially { sample(ui, vi, wi) |
56 :			wi in 0..(gridSize-1),
57 :			vi in 0..(gridSize-1),
58 :			ui in 0..(gridSize-1) };

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