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shift_view with geodesic-movement disabled is now based on Lie exponentials (NYI: SL2, Berger)

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Zeno Rogue 2022-05-06 02:36:16 +02:00
parent 97c7aef1a9
commit 1c907be9da
1 changed files with 35 additions and 4 deletions
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39
hypgraph.cpp
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@ -2952,16 +2952,47 @@ EX void rotate_view(transmatrix T) {
if(!prod && !rug::rugged) current_display->which_copy = T * current_display->which_copy; if(!prod && !rug::rugged) current_display->which_copy = T * current_display->which_copy;
} }
EX hyperpoint lie_exp(hyperpoint h) {
if(nil) {
h[3] = 1;
h[2] += h[0] * h[1] / 2;
}
else if(sol) {
h[3] = 1;
h[0] *= (exp(-h[2]) - 1) / -h[2];
h[1] *= (exp(+h[2]) - 1) / h[2];
}
else if(sol && nih) {
h[3] = 1;
ld z = h[2] * log(2);
h[0] *= (exp(-z) - 1) / -z;
z = h[2] * log(3);
h[1] *= (exp(+z) - 1) / z;
}
else if(nih) {
h[3] = 1;
ld z = h[2] * log(2);
h[0] *= (exp(+z) - 1) / z;
z = h[2] * log(3);
h[1] *= (exp(+z) - 1) / z;
}
else if(sl2) {
/* not implemented */
}
return h;
}
/** shift the view according to the given tangent vector */ /** shift the view according to the given tangent vector */
EX transmatrix get_shift_view_of(const hyperpoint H, const transmatrix V) { EX transmatrix get_shift_view_of(const hyperpoint H, const transmatrix V) {
if(!nonisotropic && !stretch::in()) { if(!nonisotropic && !stretch::in()) {
return rgpushxto0(direct_exp(lp_iapply(H))) * V; return rgpushxto0(direct_exp(lp_iapply(H))) * V;
} }
else if(!nisot::geodesic_movement) { else if(!nisot::geodesic_movement) {
transmatrix IV = view_inverse(V); transmatrix IV = view_inverse(View);
nisot::fixmatrix(IV); transmatrix view_shift = eupush( tC0(IV) );
const transmatrix V1 = iview_inverse(IV); transmatrix rot = View * view_shift;
return V1 * eupush(IV * eupush(H) * V1 * C0); hyperpoint tH = lie_exp(inverse(rot) * H);
return rot * eupush(tH) * inverse(view_shift);
} }
else { else {
return iview_inverse(nisot::parallel_transport(view_inverse(V), -H)); return iview_inverse(nisot::parallel_transport(view_inverse(V), -H));