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circumscribe for H3 and S3

This commit is contained in:
Zeno Rogue 2021-07-08 20:58:37 +02:00
parent ccc82866a9
commit 374e6a4ca9
1 changed files with 36 additions and 0 deletions
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36
hyperpoint.cpp
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@ -1639,6 +1639,42 @@ EX hyperpoint circumscribe(hyperpoint a, hyperpoint b, hyperpoint c) {
return h;
}
EX ld inner3(hyperpoint h1, hyperpoint h2) {
return
hyperbolic ? h1[LDIM] * h2[LDIM] - h1[0] * h2[0] - h1[1] * h2[1] - h1[2]*h2[2]:
sphere ? h1[LDIM] * h2[LDIM] + h1[0] * h2[0] + h1[1] * h2[1] + h1[2]*h2[2]:
h1[0] * h2[0] + h1[1] * h2[1];
}
/** circumscribe for H3 and S3 (not for E3 yet!) */
EX hyperpoint circumscribe(hyperpoint a, hyperpoint b, hyperpoint c, hyperpoint d) {
array<hyperpoint, 4> ds = { b-a, c-a, d-a, C0 };
for(int i=0; i<3; i++) {
if(inner3(ds[i],ds[i]) < 0) {
ds[i] = ds[i] / sqrt(-inner3(ds[i], ds[i]));
for(int j=i+1; j<4; j++)
ds[j] = ds[j] + ds[i] * inner3(ds[i], ds[j]);
}
else {
ds[i] = ds[i] / sqrt(inner3(ds[i], ds[i]));
for(int j=i+1; j<4; j++)
ds[j] = ds[j] - ds[i] * inner3(ds[i], ds[j]);
}
}
hyperpoint& h = ds[3];
if(h[3] < 0) h = -h;
ld i = inner3(h, h);
if(i > 0) h /= sqrt(i);
else h /= -sqrt(-i);
return h;
}
EX bool clockwise(hyperpoint h1, hyperpoint h2) {
return h1[0] * h2[1] > h1[1] * h2[0];