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hyperrogue/fieldpattern.cpp

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// Hyperbolic Rogue -- implementation of the quotient geometries based on fields
// Copyright (C) 2011-2018 Zeno Rogue, see 'hyper.cpp' for details
namespace hr {
namespace fieldpattern {
extern int subpathid;
extern int subpathorder;
bool isprime(int n) {
for(int k=2; k<n; k++) if(n%k == 0) return false;
return true;
}
struct matrix {
int a[3][3];
int* operator [] (int k) { return a[k]; }
const int* operator [] (int k) const { return a[k]; }
};
bool operator == (const matrix& A, const matrix& B) {
for(int i=0; i<3; i++) for(int j=0; j<3; j++)
if(A[i][j] != B[i][j]) return false;
return true;
}
bool operator != (const matrix& A, const matrix& B) {
for(int i=0; i<3; i++) for(int j=0; j<3; j++)
if(A[i][j] != B[i][j]) return true;
return false;
}
bool operator < (const matrix& A, const matrix& B) {
for(int i=0; i<3; i++) for(int j=0; j<3; j++)
if(A[i][j] != B[i][j]) return A[i][j] < B[i][j];
return false;
}
int btspin(int id, int d) {
return S7*(id/S7) + (id + d) % S7;
}
struct fpattern {
int Prime, wsquare, Field;
// we perform our computations in the field Z_Prime[w] where w^2 equals wsquare
// (or simply Z_Prime for wsquare == 0)
#define EASY
// 'easy' assumes that all elements of the field actually used
// are of form n or mw (not n+mw), and cs and ch are both of form n
// by experimentation, such cs and ch always exist
// many computations are much simpler under that assumption
#ifndef EASY
static int neasy;
int m(int x) { x %= Prime; if(x<0) x+= Prime; return x; }
#endif
int sub(int a, int b) {
#ifdef EASY
return (a + b * (Prime-1)) % Prime;
#else
return m(a%Prime-b%Prime) + Prime * m(a/Prime-b/Prime);
#endif
}
int add(int a, int b) {
#ifdef EASY
return (a+b)%Prime;
#else
return m(a%Prime+b%Prime) + Prime * m(a/Prime+b/Prime);
#endif
}
int mul(int tx, int ty) {
#ifdef EASY
return (tx*ty*((tx<0&&ty<0)?wsquare:1)) % Prime;
#else
if(tx >= Prime && tx % Prime) neasy++;
if(ty >= Prime && ty % Prime) neasy++;
int x[2], y[2], z[3];
for(int i=0; i<3; i++) z[i] = 0;
for(int i=0; i<2; i++)
x[i] = tx%Prime, tx /= Prime;
for(int i=0; i<2; i++)
y[i] = ty%Prime, ty /= Prime;
for(int i=0; i<2; i++)
for(int j=0; j<2; j++)
z[i+j] = (z[i+j] + x[i] * y[j]) % Prime;
z[0] += z[2] * wsquare;
return m(z[0]) + Prime * m(z[1]);
#endif
}
int sqr(int x) { return mul(x,x); }
matrix mmul(const matrix& A, const matrix& B) {
matrix res;
for(int i=0; i<3; i++) for(int k=0; k<3; k++) {
#ifdef EASY
res[i][k] =
(mul(A[i][0], B[0][k]) + mul(A[i][1], B[1][k]) + mul(A[i][2], B[2][k])) % Prime;
#else
int t=0;
for(int j=0; j<3; j++) t = add(t, mul(A[i][j], B[j][k]));
res[i][k] = t;
#endif
}
return res;
}
map<matrix, int> matcode;
vector<matrix> matrices;
vector<string> qpaths;
vector<matrix> qcoords;
matrix Id, R, P;
matrix strtomatrix(string s) {
matrix res = Id;
matrix m = Id;
for(int i=isize(s)-1; i>=0; i--)
if(s[i] == 'R') res = mmul(R, res);
else if (s[i] == 'P') res = mmul(P, res);
else if (s[i] == 'x') { m[0][0] = -1; res = mmul(m, res); m[0][0] = +1; }
else if (s[i] == 'y') { m[1][1] = -1; res = mmul(m, res); m[1][1] = +1; }
else if (s[i] == 'z') { m[2][2] = -1; res = mmul(m, res); m[2][2] = +1; }
return res;
}
void addas(const matrix& M, int i) {
if(!matcode.count(M)) {
matcode[M] = i;
for(int j=0; j<isize(qcoords); j++)
addas(mmul(M, qcoords[j]), i);
}
}
void add(const matrix& M) {
if(!matcode.count(M)) {
int i = matrices.size();
matcode[M] = i, matrices.push_back(M);
for(int j=0; j<isize(qcoords); j++)
addas(mmul(M, qcoords[j]), i);
add(mmul(R, M));
}
}
#define MXF 1000000
vector<int> connections;
vector<int> inverses;
vector<int> rrf; // rrf[i] equals gmul(i, S7-1)
vector<int> rpf; // rpf[i] equals gmul(i, S7)
matrix mpow(matrix M, int N) {
while((N&1) == 0) N >>= 1, M = mmul(M, M);
matrix res = M;
N >>= 1;
while(N) {
M = mmul(M,M); if(N&1) res = mmul(res, M);
N >>= 1;
}
return res;
}
int gmul(int a, int b) { return matcode[mmul(matrices[a], matrices[b])]; }
int gpow(int a, int N) { return matcode[mpow(matrices[a], N)]; }
pair<int,bool> gmul(pair<int, bool> a, int b) {
return make_pair(gmul(a.first,b), a.second);
}
int order(const matrix& M) {
int cnt = 1;
matrix Po = M;
while(Po != Id) Po = mmul(Po, M), cnt++;
return cnt;
}
string decodepath(int i) {
string s;
while(i) {
if(i % S7) i--, s += 'R';
else i = connections[i], s += 'P';
}
return s;
}
int orderstats();
int cs, sn, ch, sh;
int solve() {
for(int a=0; a<3; a++) for(int b=0; b<3; b++) Id[a][b] = a==b?1:0;
if(!isprime(Prime)) {
return 1;
}
for(int pw=1; pw<3; pw++) {
if(pw>3) break;
Field = pw==1? Prime : Prime*Prime;
if(pw == 2) {
for(wsquare=1; wsquare<Prime; wsquare++) {
int roots = 0;
for(int a=0; a<Prime; a++) if((a*a)%Prime == wsquare) roots++;
if(!roots) break;
}
} else wsquare = 0;
#ifdef EASY
std::vector<int> sqrts(Prime, 0);
for(int k=1-Prime; k<Prime; k++) sqrts[sqr(k)] = k;
int fmax = Prime;
#else
std::vector<int> sqrts(Field);
for(int k=0; k<Field; k++) sqrts[sqr(k)] = k;
int fmax = Field;
#endif
if(Prime == 13 && wsquare && false) {
for(int i=0; i<Prime; i++) printf("%3d", sqrts[i]);
printf("\n");
}
for(int i=0; i<3; i++) for(int j=0; j<3; j++)
R[i][j] = P[i][j] = i==j ? 1 : 0;
for(cs=0; cs<fmax; cs++) {
int sb = sub(1, sqr(cs));
sn = sqrts[sb];
R[0][0] = cs; R[1][1] = cs;
R[0][1] = sn; R[1][0] = sub(0, sn);
matrix Z = R;
for(int i=1; i<S7; i++) {
if(Z == Id) goto nextcs;
Z = mmul(Z, R);
}
if(Z != Id) continue;
if(R[0][0] == 1) continue;
for(ch=2; ch<fmax; ch++) {
int chx = sub(mul(ch,ch), 1);
sh = sqrts[chx];
P[0][0] = sub(0, ch);
P[0][2] = sub(0, sh);
P[1][1] = Prime-1;
P[2][0] = sh;
P[2][2] = ch;
matrix Z1 = mmul(P, R);
matrix Z = Z1;
for(int i=1; i<S3; i++) {
if(Z == Id) goto nextch;
Z = mmul(Z, Z1);
}
if(Z == Id) return 0;
nextch: ;
}
nextcs: ;
}
}
return 2;
}
void build() {
for(int i=0; i<isize(qpaths); i++) {
matrix M = strtomatrix(qpaths[i]);
qcoords.push_back(M);
printf("Solved %s as matrix of order %d\n", qpaths[i].c_str(), order(M));
}
matcode.clear(); matrices.clear();
add(Id);
if(isize(matrices) != S7) { printf("Error: rotation crash #1 (%d)\n", isize(matrices)); exit(1); }
connections.clear();
for(int i=0; i<(int)matrices.size(); i++) {
matrix M = matrices[i];
matrix PM = mmul(P, M);
add(PM);
if(isize(matrices) % S7) { printf("Error: rotation crash (%d)\n", isize(matrices)); exit(1); }
if(!matcode.count(PM)) { printf("Error: not marked\n"); exit(1); }
connections.push_back(matcode[PM]);
}
DEBB(DF_FIELD, (debugfile, "Computing inverses...\n"));
int N = isize(matrices);
DEBB(DF_FIELD, (debugfile, "Number of heptagons: %d\n", N));
rrf.resize(N); rrf[0] = S7-1;
for(int i=0; i<N; i++)
rrf[btspin(i,1)] = btspin(rrf[i], 1),
rrf[connections[i]] = connections[rrf[i]];
rpf.resize(N); rpf[0] = S7;
for(int i=0; i<N; i++)
rpf[btspin(i,1)] = btspin(rpf[i], 1),
rpf[connections[i]] = connections[rpf[i]];
inverses.resize(N);
inverses[0] = 0;
for(int i=0; i<N; i++) // inverses[i] = gpow(i, N-1);
inverses[btspin(i,1)] = rrf[inverses[i]], // btspin(inverses[i],6),
inverses[connections[i]] = rpf[inverses[i]];
int errs = 0;
for(int i=0; i<N; i++) if(gmul(i, inverses[i])) errs++;
if(errs) printf("errs = %d\n", errs);
if(0) for(int i=0; i<isize(matrices); i++) {
printf("%5d/%4d", connections[i], inverses[i]);
if(i%S7 == S7-1) printf("\n");
}
DEBB(DF_FIELD, (debugfile, "Built.\n"));
}
static const int MAXDIST = 120;
vector<char> disthep;
vector<char> disthex;
vector<char> distwall, distriver, distwall2, distriverleft, distriverright, distflower;
int distflower0;
vector<eItem> markers;
int getdist(pair<int,bool> a, vector<char>& dists) {
if(!a.second) return dists[a.first];
int m = MAXDIST;
int ma = dists[a.first];
int mb = dists[connections[btspin(a.first, 3)]];
int mc = dists[connections[btspin(a.first, 4)]];
m = min(m, 1 + ma);
m = min(m, 1 + mb);
m = min(m, 1 + mc);
if(m <= 2 && ma+mb+mc <= m*3-2) return m-1; // special case
m = min(m, 2 + dists[connections[btspin(a.first, 2)]]);
m = min(m, 2 + dists[connections[btspin(a.first, 5)]]);
m = min(m, 2 + dists[connections[btspin(connections[btspin(a.first, 3)], 5)]]);
return m;
}
int getdist(pair<int,bool> a, pair<int,bool> b) {
if(a.first == b.first) return a.second == b.second ? 0 : 1;
if(b.first) a.first = gmul(a.first, inverses[b.first]), b.first = 0;
return getdist(a, b.second ? disthex : disthep);
}
int maxdist, otherpole, circrad, wallid, wallorder, riverid;
int dijkstra(vector<char>& dists, vector<int> indist[MAXDIST]) {
int N = connections.size();
dists.resize(N);
for(int i=0; i<N; i++) dists[i] = MAXDIST-1;
int maxd = 0;
for(int i=0; i<MAXDIST; i++) while(!indist[i].empty()) {
int at = indist[i].back();
indist[i].pop_back();
if(dists[at] <= i) continue;
maxd = i;
dists[at] = i;
for(int q=0; q<S7; q++) {
dists[at] = i;
if(PURE) // todo-variation: PURE here?
indist[i+1].push_back(connections[at]);
else {
indist[i+2].push_back(connections[at]);
indist[i+3].push_back(connections[btspin(connections[at], 2)]);
}
at = btspin(at, 1);
}
}
return maxd;
}
void analyze() {
DEBB(DF_FIELD, (debugfile, "variation = %d\n", int(variation)));
int N = connections.size();
markers.resize(N);
vector<int> indist[MAXDIST];
indist[0].push_back(0);
int md0 = dijkstra(disthep, indist);
indist[1].push_back(0);
indist[1].push_back(connections[3]);
indist[1].push_back(connections[4]);
indist[2].push_back(connections[btspin(connections[3], 5)]);
indist[2].push_back(connections[2]);
indist[2].push_back(connections[5]);
int md1 = dijkstra(disthex, indist);
maxdist = max(md0, md1);
otherpole = 0;
for(int i=0; i<N; i+=S7) {
int mp = 0;
for(int q=0; q<S7; q++) if(disthep[connections[i+q]] < disthep[i]) mp++;
if(mp == S7) {
bool eq = true;
for(int q=0; q<S7; q++) if(disthep[connections[i+q]] != disthep[connections[i]]) eq = false;
if(eq) {
// for(int q=0; q<S7; q++) printf("%3d", disthep[connections[i+q]]);
// printf(" (%2d) at %d\n", disthep[i], i);
if(disthep[i] > disthep[otherpole]) otherpole = i;
// for(int r=0; r<S7; r++) {
// printf("Matrix: "); for(int a=0; a<3; a++) for(int b=0; b<3; b++)
// printf("%4d", matrices[i+r][a][b]); printf("\n");
// }
}
}
}
circrad = 99;
for(int i=0; i<N; i++) for(int u=2; u<4; u++) if(disthep[i] < circrad)
if(disthep[connections[i]] < disthep[i] && disthep[connections[btspin(i,u)]] < disthep[i])
circrad = disthep[i];
DEBB(DF_FIELD, (debugfile, "maxdist = %d otherpole = %d circrad = %d\n", maxdist, otherpole, circrad));
matrix PRRR = strtomatrix("PRRR");
matrix PRRPRRRRR = strtomatrix("PRRPRRRRR");
matrix PRRRP = strtomatrix("PRRRP");
matrix PRP = strtomatrix("PRP");
matrix PR = strtomatrix("PR");
matrix Wall = strtomatrix("RRRPRRRRRPRRRP");
wallorder = order(Wall);
wallid = matcode[Wall];
DEBB(DF_FIELD, (debugfile, "wall order = %d\n", wallorder));
#define SETDIST(X, d, it) {int c = matcode[X]; indist[d].push_back(c); if(it == itNone) ; else if(markers[c] && markers[c] != it) markers[c] = itBuggy; else markers[c] = it; }
matrix W = Id;
for(int i=0; i<wallorder; i++) {
SETDIST(W, 0, itAmethyst)
W = mmul(W, Wall);
}
W = P;
for(int i=0; i<wallorder; i++) {
SETDIST(W, 0, itEmerald)
W = mmul(W, Wall);
}
int walldist = dijkstra(distwall, indist);
DEBB(DF_FIELD, (debugfile, "wall dist = %d\n", walldist));
W = strtomatrix("RRRRPR");
for(int j=0; j<wallorder; j++) {
W = mmul(W, Wall);
for(int i=0; i<wallorder; i++) {
SETDIST(W, 0, itNone)
SETDIST(mmul(PRRR, W), 1, itNone)
W = mmul(Wall, W);
}
}
dijkstra(distwall2, indist);
int rpushid = matcode[PRRPRRRRR];
riverid = 0;
for(int i=0; i<N; i++) {
int j = i;
int ipush = gmul(rpushid, i);
for(int k=0; k<wallorder; k++) {
if(ipush == j) {
DEBB(DF_FIELD, (debugfile, "River found at %d:%d\n", i, k));
riverid = i;
goto riveridfound;
}
j = gmul(j, wallid);
}
}
riveridfound: ;
W = strtomatrix("RRRRPR");
for(int j=0; j<wallorder; j++) {
W = mmul(W, Wall);
for(int i=0; i<wallorder; i++) {
if(i == 7) SETDIST(W, 0, itCoast)
if(i == 3) SETDIST(mmul(PRRRP, W), 0, itWhirlpool)
W = mmul(Wall, W);
}
}
dijkstra(PURE ? distriver : distflower, indist);
W = matrices[riverid];
for(int i=0; i<wallorder; i++) {
SETDIST(W, 0, itStatue)
W = mmul(W, Wall);
}
W = mmul(P, W);
for(int i=0; i<wallorder; i++) {
SETDIST(W, 0, itSapphire)
W = mmul(W, Wall);
}
W = mmul(PRP, matrices[riverid]);
for(int i=0; i<wallorder; i++) {
SETDIST(W, 1, itShard)
W = mmul(W, Wall);
}
W = mmul(PR, matrices[riverid]);
for(int i=0; i<wallorder; i++) {
SETDIST(W, 1, itGold)
W = mmul(W, Wall);
}
int riverdist = dijkstra(PURE ? distflower : distriver, indist);
DEBB(DF_FIELD, (debugfile, "river dist = %d\n", riverdist));
for(int i=0; i<isize(currfp.matrices); i++)
if(currfp.distflower[i] == 0) {
distflower0 = currfp.inverses[i]+1;
break;
}
if(!PURE) {
W = matrices[riverid];
for(int i=0; i<wallorder; i++) {
SETDIST(W, 0, itStatue)
W = mmul(W, Wall);
}
W = mmul(PR, matrices[riverid]);
for(int i=0; i<wallorder; i++) {
SETDIST(W, 0, itGold)
W = mmul(W, Wall);
}
W = mmul(P, matrices[riverid]);
for(int i=0; i<wallorder; i++) {
SETDIST(W, 1, itSapphire)
W = mmul(W, Wall);
}
dijkstra(distriverleft, indist);
W = mmul(PRP, matrices[riverid]);
for(int i=0; i<wallorder; i++) {
SETDIST(W, 0, itShard)
W = mmul(W, Wall);
}
W = mmul(P, matrices[riverid]);
for(int i=0; i<wallorder; i++) {
SETDIST(W, 0, itSapphire)
W = mmul(W, Wall);
}
W = matrices[riverid];
for(int i=0; i<wallorder; i++) {
SETDIST(W, 1, itStatue)
W = mmul(W, Wall);
}
dijkstra(distriverright, indist);
}
else {
W = strtomatrix("RRRRPR");
for(int j=0; j<wallorder; j++) {
W = mmul(W, Wall);
for(int i=0; i<wallorder; i++) {
if(i == 7) SETDIST(W, 0, itCoast)
W = mmul(Wall, W);
}
}
dijkstra(distriverleft, indist);
W = strtomatrix("RRRRPR");
for(int j=0; j<wallorder; j++) {
W = mmul(W, Wall);
for(int i=0; i<wallorder; i++) {
if(i == 3) SETDIST(mmul(PRRRP, W), 0, itWhirlpool)
W = mmul(Wall, W);
}
}
dijkstra(distriverright, indist);
}
DEBB(DF_FIELD, (debugfile, "wall-river distance = %d\n", distwall[riverid]));
DEBB(DF_FIELD, (debugfile, "river-wall distance = %d\n", distriver[0]));
}
bool easy(int i) {
return i < Prime || !(i % Prime);
}
// 11 * 25
// (1+z+z^3) * (1+z^3+z^4) ==
// 1+z+z^7 == 1+z+z^2(z^5) == 1+z+z^2(1+z^2) = 1+z+z^2+z^4
void init(int p) {
Prime = p;
if(solve()) {
printf("error: could not solve the fieldpattern\n");
exit(1);
}
build();
}
fpattern(int p) {
if(!p) return;
init(p);
}
void findsubpath() {
int N = isize(matrices);
for(int i=1; i<N; i++)
if(gpow(i, Prime) == 0) {
subpathid = i;
subpathorder = Prime;
DEBB(DF_FIELD, (debugfile, "Subpath found: %s\n", decodepath(i).c_str()));
return;
}
}
};
int fpattern::orderstats() {
int N = isize(matrices);
#define MAXORD 10000
int ordcount[MAXORD];
int ordsample[MAXORD];
for(int i=0; i<MAXORD; i++) ordcount[i] = 0;
for(int i=0; i<N; i++) {
int cnt = order(matrices[i]);
if(cnt < MAXORD) {
if(!ordcount[cnt]) ordsample[cnt] = i;
ordcount[cnt]++;
}
}
printf("Listing:\n");
for(int i=0; i<MAXORD; i++) if(ordcount[i])
printf("Found %4d matrices of order %3d: %s\n", ordcount[i], i, decodepath(ordsample[i]).c_str());
return ordsample[Prime];
}
fpattern fp43(43);
void info() {
fpattern fp(0);
int cases = 0, hard = 0;
for(int p=0; p<500; p++) {
fp.Prime = p;
if(fp.solve() == 0) {
printf("%4d: wsquare=%d cs=%d sn=%d ch=%d sh=%d\n",
p, fp.wsquare, fp.cs, fp.sn, fp.ch, fp.sh);
cases++;
if(!fp.easy(fp.cs) || !fp.easy(fp.sn) || !fp.easy(fp.ch) || !fp.easy(fp.sn))
hard++;
#ifndef EASY
neasy = 0;
#endif
fp.build();
#ifndef EASY
printf("Not easy: %d\n", neasy);
#endif
int N = isize(fp.matrices);
int left = N / fp.Prime;
printf("Prime decomposition: %d = %d", N, fp.Prime);
for(int p=2; p<=left; p++) while(left%p == 0) printf("*%d", p), left /= p;
printf("\n");
printf("Order of RRP is: %d\n", fp.order(fp.strtomatrix("RRP")));
printf("Order of RRRP is: %d\n", fp.order(fp.strtomatrix("RRRP")));
printf("Order of RRRPRRRRRPRRRP is: %d\n", fp.order(fp.strtomatrix("RRRPRRRRRPRRRP")));
}
}
printf("cases found = %d (%d hard)\n", cases, hard);
}
fpattern current_quotient_field(0), fp_invalid(0);
bool quotient_field_changed;
fpattern& getcurrfp() {
if(geometry == gFieldQuotient && quotient_field_changed)
return current_quotient_field;
if(S7 == 8 && S3 == 3) {
static fpattern fp(17);
return fp;
}
if(S7 == 5 && S3 == 4) {
static fpattern fp(11);
return fp;
}
if(S7 == 6 && S3 == 4) {
static fpattern fp(13);
return fp;
}
if(S7 == 7 && S3 == 4) {
static fpattern fp(13);
return fp;
}
if(sphere || euclid) return fp_invalid;
if(S7 == 7 && S3 == 3)
return fp43;
return fp_invalid;
}
// extra information for field quotient extra configuration
vector<fgeomextra> fgeomextras = {
fgeomextra(gNormal, 3),
fgeomextra(gOctagon, 1),
fgeomextra(g45, 0),
fgeomextra(g46, 3),
fgeomextra(g47, 0),
/* fgeomextra(gSphere, 0),
fgeomextra(gSmallSphere, 0), -> does not find the prime
fgeomextra(gEuclid, 0),
fgeomextra(gEuclidSquare, 0),
fgeomextra(gTinySphere, 0) */
};
int current_extra = 0;
void nextPrime(fgeomextra& ex) {
dynamicval<eGeometry> g(geometry, ex.base);
int nextprime;
if(isize(ex.primes))
nextprime = ex.primes.back().p + 1;
else
nextprime = 2;
while(true) {
fieldpattern::fpattern fp(0);
fp.Prime = nextprime;
if(fp.solve() == 0) {
fp.build();
int cells = fp.matrices.size() / S7;
ex.primes.emplace_back(primeinfo{nextprime, cells, (bool) fp.wsquare});
break;
}
nextprime++;
}
}
void nextPrimes(fgeomextra& ex) {
while(isize(ex.primes) < 4)
nextPrime(ex);
}
void enableFieldChange() {
fgeomextra& gxcur = fgeomextras[current_extra];
fieldpattern::quotient_field_changed = true;
nextPrimes(gxcur);
dynamicval<eGeometry> g(geometry, gFieldQuotient);
ginf[geometry].sides = ginf[gxcur.base].sides;
ginf[geometry].vertex = ginf[gxcur.base].vertex;
ginf[geometry].distlimit = ginf[gxcur.base].distlimit;
fieldpattern::current_quotient_field.init(gxcur.primes[gxcur.current_prime_id].p);
}
}
#define currfp fieldpattern::getcurrfp()
int currfp_gmul(int a, int b) { return currfp.gmul(a,b); }
int currfp_inverses(int i) { return currfp.inverses[i]; }
int currfp_distwall(int i) { return currfp.distwall[i]; }
}
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