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hyperrogue/devmods/solv-table.cpp
2019-10-05 18:53:51 +02:00

342 lines
9.9 KiB
C++

// This generates the inverse geodesics tables.
// Usage:
// [executable] -geo sol -write solv-geodesics.dat
// -geo 3:2 -write shyp-geodesics.dat
// -geo 3:1/2 -write ssol-geodesics.dat
// -exit
// You can also do -geo [...] -build to build and test the table
// without writing it.
// By default this generates 64x64x64 tables.
// Add e.g. '-dim 128 128 128' before -write to generate
// a more/less precise table.
#include "../hyper.h"
#include <thread>
#include <mutex>
namespace hr {
transmatrix parabolic1(ld u);
namespace nisot {
typedef hyperpoint pt;
using solnihv::x_to_ix;
ld z_to_iz(ld z) { if(sol) return tanh(z); else return tanh(z/4)/2 + .5; }
ptlow be_low(hyperpoint x) { return ptlow({float(x[0]), float(x[1]), float(x[2])}); }
template<class T> void parallelize(int threads, int Nmin, int Nmax, T action) {
std::vector<std::thread> v;
for(int k=0; k<threads; k++)
v.emplace_back([&,k] () {
for(int i=Nmin+k; i < Nmax; i += threads) action(k, i);
});
for(std::thread& t:v) t.join();
}
ld solerror(hyperpoint ok, hyperpoint chk) {
auto zok = point3( x_to_ix(ok[0]), x_to_ix(ok[1]), z_to_iz(ok[2]) );
auto zchk = point3( x_to_ix(chk[0]), x_to_ix(chk[1]), z_to_iz(chk[2]) );
return hypot_d(3, zok - zchk);
}
hyperpoint iterative_solve(hyperpoint xp, hyperpoint candidate, int prec, ld minerr, bool debug = false) {
transmatrix T = Id; T[0][1] = 8; T[2][2] = 5;
auto f = [&] (hyperpoint x) { return nisot::numerical_exp(x, prec); }; // T * x; };
auto ver = f(candidate);
ld err = solerror(xp, ver);
auto at = candidate;
ld eps = 1e-6;
hyperpoint c[3];
for(int a=0; a<3; a++) c[a] = point3(a==0, a==1, a==2);
while(err > minerr) {
if(debug) println(hlog, "\n\nf(", at, "?) = ", ver, " (error ", err, ")");
array<hyperpoint, 3> pnear;
for(int a=0; a<3; a++) {
auto x = at + c[a] * eps;
if(debug) println(hlog, "f(", x, ") = ", f(x), " = y + ", f(x)-ver );
pnear[a] = (f(x) - ver) / eps; // (direct_exp(at + c[a] * eps, prec) - ver) / eps;
}
transmatrix U = Id;
for(int a=0; a<3; a++)
for(int b=0; b<3; b++)
U[a][b] = pnear[b][a];
hyperpoint diff = (xp - ver);
hyperpoint bonus = inverse(U) * diff;
if(hypot_d(3, bonus) > 0.1) bonus = bonus * 0.1 / hypot_d(3, bonus);
int fixes = 0;
if(debug)
println(hlog, "\nU = ", U, "\ndiff = ", diff, "\nbonus = ", bonus, "\n");
nextfix:
hyperpoint next = at + bonus;
hyperpoint nextver = f(next);
ld nexterr = solerror(xp, nextver);
if(debug) println(hlog, "f(", next, ") = ", nextver, ", error = ", nexterr);
if(nexterr < err) {
// println(hlog, "reduced error ", err, " to ", nexterr);
at = next;
ver = nextver;
err = nexterr;
continue;
}
else {
bonus /= 2;
fixes++;
if(fixes > 10) {
if(err > 999) {
for(ld s = 1; abs(s) > 1e-9; s *= 0.5)
for(int k=0; k<27; k++) {
int kk = k;
next = at;
for(int i=0; i<3; i++) { if(kk%3 == 1) next[i] += s; if(kk%3 == 2) next[i] -= s; kk /= 3; }
// next = at + c[k] * s;
nextver = f(next);
nexterr = solerror(xp, nextver);
// println(hlog, "f(", next, ") = ", nextver, ", error = ", nexterr);
if(nexterr < err) { at = next; ver = nextver; err = nexterr; goto nextiter; }
}
println(hlog, "cannot improve error ", err);
exit(1);
}
break;
}
goto nextfix;
}
nextiter: ;
}
return at;
}
ptlow mlow(ld x, ld y, ld z) { return ptlow({float(x), float(y), float(z)}); }
hyperpoint atxyz(ld x, ld y, ld z) { return hyperpoint({x, y, z, 1}); }
ptlow operator +(ptlow a, ptlow b) { return mlow(a[0]+b[0], a[1]+b[1], a[2]+b[2]); }
ptlow operator -(ptlow a, ptlow b) { return mlow(a[0]-b[0], a[1]-b[1], a[2]-b[2]); }
ptlow operator *(ptlow a, ld x) { return mlow(a[0]*x, a[1]*x, a[2]*x); }
ptlow can(hyperpoint x) {
// azimuthal equidistant to Klein
ld r = sqrt(x[0] * x[0] + x[1] * x[1] + x[2] * x[2]);
if(r == 0) return mlow(0,0,0);
ld make_r = tanh(r);
ld d = make_r / r;
return mlow(x[0]*d, x[1]*d, x[2]*d);
}
hyperpoint uncan(ptlow x) {
ld r = sqrt(x[0] * x[0] + x[1] * x[1] + x[2] * x[2]);
if(r == 0) return atxyz(0,0,0);
ld make_r = atanh(r);
if(r == 1) make_r = 30;
ld d = make_r / r;
return atxyz(x[0]*d, x[1]*d, x[2]*d);
}
hyperpoint uncan_info(ptlow x) {
ld r = sqrt(x[0] * x[0] + x[1] * x[1] + x[2] * x[2]);
println(hlog, "r = ", r);
if(r == 0) return atxyz(0,0,0);
ld make_r = atanh(r);
println(hlog, "make_r = ", make_r);
ld d = make_r / r;
println(hlog, "d = ", d);
return atxyz(x[0]*d, x[1]*d, x[2]*d);
}
void fint(FILE *f, int x) { fwrite(&x, sizeof(x), 1, f); }
void ffloat(FILE *f, float x) { fwrite(&x, sizeof(x), 1, f); }
void write_table(solnihv::tabled_inverses& tab, const char *fname) {
FILE *f = fopen(fname, "wb");
fint(f, tab.PRECX);
fint(f, tab.PRECY);
fint(f, tab.PRECZ);
fwrite(&tab.tab[0], sizeof(ptlow) * tab.PRECX * tab.PRECY * tab.PRECZ, 1, f);
fclose(f);
}
void alloc_table(solnihv::tabled_inverses& tab, int X, int Y, int Z) {
tab.PRECX = X;
tab.PRECY = Y;
tab.PRECZ = Z;
tab.tab.resize(X*Y*Z);
}
ld ix_to_x(ld ix) {
ld minx = 0, maxx = 1;
for(int it=0; it<100; it++) {
ld x = (minx + maxx) / 2;
if(x_to_ix(atanh(x)) < ix) minx = x;
else maxx = x;
}
return atanh(minx);
}
ld iz_to_z(ld z) {
return nih ? atanh(z * 2 - 1)*4 : atanh(z); // atanh(z * 2 - 1);
}
ld ptd(ptlow p) {
return p[0]*p[0] + p[1]*p[1] + p[2] * p[2];
}
ptlow zflip(ptlow x) { return mlow(x[1], x[0], -x[2]); }
void build_sols(int PRECX, int PRECY, int PRECZ) {
std::mutex file_mutex;
ld max_err = 0;
auto& tab = solnihv::get_tabled();
alloc_table(tab, PRECX, PRECY, PRECZ);
int last_x = PRECX-1, last_y = PRECY-1, last_z = PRECZ-1;
auto act = [&] (int tid, int iz) {
if((nih && iz == 0) || iz == PRECZ-1) return;
auto solve_at = [&] (int ix, int iy) {
ld x = ix_to_x(ix / (PRECX-1.));
ld y = ix_to_x(iy / (PRECY-1.));
ld z = iz_to_z(iz / (PRECZ-1.));
auto v = hyperpoint ({x,y,z,1});
vector<hyperpoint> candidates;
hyperpoint cand;
candidates.push_back(atxyz(0,0,0));
static constexpr int prec = 100;
// sort(candidates.begin(), candidates.end(), [&] (hyperpoint a, hyperpoint b) { return solerror(v, direct_exp(a, prec)) > solerror(v, direct_exp(b, prec)); });
// cand_best = candidates.back();
vector<hyperpoint> solved_candidates;
for(auto c: candidates) {
auto solt = iterative_solve(v, c, prec, 1e-6);
solved_candidates.push_back(solt);
if(solerror(v, nisot::numerical_exp(solt, prec)) < 1e-9) break;
}
sort(solved_candidates.begin(), solved_candidates.end(), [&] (hyperpoint a, hyperpoint b) { return solerror(v, nisot::numerical_exp(a, prec)) > solerror(v, nisot::numerical_exp(b, prec)); });
cand = solved_candidates.back();
auto xerr = solerror(v, nisot::numerical_exp(cand, prec));
if(xerr > 1e-3) {
println(hlog, format("[%2d %2d %2d] ", iz, iy, ix));
println(hlog, "f(?) = ", v);
println(hlog, "f(", cand, ") = ", nisot::numerical_exp(cand, prec));
println(hlog, "error = ", xerr);
println(hlog, "canned = ", can(cand));
max_err = xerr;
/*
hyperpoint h1 = uncan(solution[iz][iy-1][ix]);
hyperpoint h2 = uncan(solution[iz][iy][ix-1]);
hyperpoint h3 = uncan(solution[iz][iy-1][ix-1]);
hyperpoint h4 = h1 + h2 - h3;
solution[iz][iy][ix] = can(h4);
*/
return;
}
auto& so = tab.get_int(ix, iy, iz);
so = can(cand);
for(int z=0; z<3; z++) if(isnan(so[z]) || isinf(so[z])) {
println(hlog, cand, "canned to ", so);
exit(4);
}
};
for(int it=0; it<max(last_x, last_y); it++) {
for(int a=0; a<it; a++) {
if(it < last_x && a < last_y) solve_at(it, a);
if(a < last_x && it < last_y) solve_at(a, it);
}
if(it < last_x && it < last_y) solve_at(it, it);
std::lock_guard<std::mutex> fm(file_mutex);
println(hlog, format("%2d: %2d", iz, it));
}
};
parallelize(PRECZ, 0, PRECZ, act);
for(int x=0; x<last_x; x++)
for(int y=0; y<last_y; y++) {
for(int z=last_z; z<PRECZ; z++)
tab.get_int(x,y,z) = tab.get_int(x,y,z-1) * 2 - tab.get_int(x,y,z-2);
if(nih)
tab.get_int(x,y,0) = tab.get_int(x,y,1) * 2 - tab.get_int(x,y,2);
}
for(int x=0; x<last_x; x++)
for(int y=last_y; y<PRECY; y++)
for(int z=0; z<PRECZ; z++)
tab.get_int(x,y,z) = tab.get_int(x,y-1,z) * 2 - tab.get_int(x,y-2,z);
for(int x=last_x; x<PRECX; x++)
for(int y=0; y<PRECY; y++)
for(int z=0; z<PRECZ; z++)
tab.get_int(x,y,z) = tab.get_int(x-1,y,z) * 2 - tab.get_int(x-2,y,z);
}
int dimX, dimY, dimZ;
int readArgs() {
using namespace arg;
if(0) ;
else if(argis("-dim")) {
PHASEFROM(2);
shift(); dimX = argi();
shift(); dimY = argi();
shift(); dimZ = argi();
}
else if(argis("-build")) {
PHASEFROM(2);
build_sols(dimX, dimY, dimZ);
}
else if(argis("-write")) {
PHASEFROM(2);
shift();
build_sols(dimX, dimY, dimZ);
write_table(solnihv::get_tabled(), argcs());
}
else return 1;
return 0;
}
auto hook = addHook(hooks_args, 100, readArgs);
}
}