mirror of
https://git.code.sf.net/p/quake/quakeforge
synced 2024-11-14 08:50:58 +00:00
b37b0180cb
If the kahan triangle area method breaks, I did something wrong with qfcc's handling of parentheses (ie, floating point math is not truly associative).
33 lines
710 B
R
33 lines
710 B
R
void printf (string fmt, ...) = #0;
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float (string s) stof = #0;
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float (float x) sqrt = #0;
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float
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heron (float a, float b, float c)
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{
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float s = (a + b + c) / 2;
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return sqrt (s*(s-a)*(s-b)*(s-c));
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}
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float
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kahan (float a, float b, float c)
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{
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float t;
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if (a < b) { t = a; a = b; b = t; }
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if (b < c) { t = b; b = c; c = t; }
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if (a < b) { t = a; a = b; b = t; }
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return sqrt ((a + (b + c))*(c - (a - b))*(c + (a - b))*(a + (b - c)))/4;
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}
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int
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main (int argc, string *argv)
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{
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float a = stof (argv[1]);
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float b = stof (argv[2]);
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float c = stof (argv[3]);
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float expt = stof (argv[4]);
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float h = heron (a, b, c);
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float k = kahan (a, b, c);
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printf ("%.9g %.9g %d\n", h, k, k == expt);
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return k != expt;
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}
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