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Make tc::Group an Eigen::Matrix (Schafli Matrix)

Makes tc::Group a direct subclass of Eigen::Matrix. Group should represent a Schlafli matrix.

Added a note that tc::solve assumes the matrix to be for a coxeter group.

In theory we could also implement the "normal" todd-coxeter and allow any Schlafli matrix as input.
This commit is contained in:
David Allemang
2021-11-01 16:58:48 -04:00
parent 6585d79ed9
commit 24d4d1873a
4 changed files with 172 additions and 213 deletions

View File

@@ -2,167 +2,150 @@
#include "core.hpp"
namespace tc {
namespace tc::group {
/**
* Construct a group from a (simplified) Schlafli Symbol of the form [a, b, ..., c]
* @param mults: The sequence of multiplicites between adjacent generators.
* Universal Coxeter Group
*/
template<unsigned int Rank>
Group <Rank> schlafli(const std::array<unsigned int, Rank - 1> &mults, const std::string &name) {
Group<Rank> g(name);
Group <Rank> U() {
std::stringstream ss;
ss << "U(" << Rank << ")";
for (int i = 0; i < Rank - 1; i++) {
g(i, i + 1) = mults[i];
Group<Rank> res;
res.name = ss.str();
res.fill(2);
return res;
}
/**
* Simplex
*/
template<unsigned int Rank>
Group <Rank> A() {
std::stringstream ss;
ss << "A(" << Rank << ")";
if (Rank == 0) {
Group<Rank> res;
res.name = ss.str();
return res;
}
std::array<unsigned int, Rank - 1> mults;
mults.fill(3);
return schlafli<Rank>(mults, ss.str());
}
/**
* Cube, Orthoplex
*/
template<unsigned int Rank>
Group <Rank> B() {
std::stringstream ss;
ss << "B(" << Rank << ")";
tc::Symbol<Rank - 1> mults;
mults.fill(3);
mults(0) = 4;
return schlafli<Rank>(mults, ss.str());
}
/**
* Demicube, Orthoplex
*/
template<unsigned int Rank>
Group <Rank> D() {
std::stringstream ss;
ss << "D(" << Rank << ")";
tc::Symbol<Rank - 1> mults;
mults.fill(3);
mults(Rank - 2) = 2;
Group<Rank> g = schlafli<Rank>(mults, ss.str());
g(1, Rank - 1) = 3;
g(Rank - 1, 1) = 3;
return g;
}
/**
* Construct a group from a (simplified) Schlafli Symbol of the form [a, b, ..., c]
* @param mults: The sequence of multiplicites between adjacent generators.
* E groups
*/
template<unsigned int Rank>
Group <Rank> schlafli(const std::array<unsigned int, Rank - 1> &mults) {
Group <Rank> E() {
std::stringstream ss;
ss << "[";
if (Rank) {
for (size_t i = 0; i < Rank - 2; ++i) {
ss << mults[i] << ",";
}
ss << mults[Rank - 1];
}
ss << "]";
ss << "E(" << Rank << ")";
tc::Symbol<Rank - 1> mults;
mults.fill(3);
mults(Rank - 2) = 2;
Group<Rank> g = schlafli<Rank>(mults, ss.str());
g(2, Rank - 1) = 3;
g(Rank - 1, 2) = 3;
return g;
}
/**
* 24 Cell
*/
Group<4> F4() {
return schlafli<4>({3, 4, 3}, "F4");
}
/**
* Hexagon
*/
Group<2> G2() {
return schlafli<2>(tc::Symbol<1>(6), "G2");
}
/**
* Icosahedron
*/
template<unsigned int Rank>
Group <Rank> H() {
std::stringstream ss;
ss << "H(" << Rank << ")";
tc::Symbol<Rank - 1> mults;
mults.fill(3);
mults(0) = 5;
return schlafli<Rank>(mults, ss.str());
}
namespace group {
/**
* Simplex
*/
template<unsigned int Rank>
Group <Rank> A() {
std::stringstream ss;
ss << "A(" << Rank << ")";
/**
* Polygonal
*/
Group<2> I2(unsigned int n) {
std::stringstream ss;
ss << "I2(" << n << ")";
if (Rank == 0)
return Group<Rank>(ss.str());
return schlafli<2>(tc::Symbol<1>(n), ss.str());
}
std::array<unsigned int, Rank - 1> mults;
mults.fill(3);
/**
* Toroidal. I2(n) * I2(m)
*/
Group<4> T(unsigned int n, unsigned int m) {
std::stringstream ss;
ss << "T(" << n << "," << m << ")";
return schlafli<Rank>(mults, ss.str());
}
return schlafli<4>({n, 2, m}, ss.str());
}
/**
* Cube, Orthoplex
*/
template<unsigned int Rank>
Group <Rank> B() {
std::stringstream ss;
ss << "B(" << Rank << ")";
/**
* Toroidal. T(n, n)
*/
Group<4> T(unsigned int n) {
std::stringstream ss;
ss << "T(" << n << ")";
std::array<unsigned int, Rank - 1> mults;
mults.fill(3);
mults[0] = 4;
return schlafli<Rank>(mults, ss.str());
}
/**
* Demicube, Orthoplex
*/
template<unsigned int Rank>
Group <Rank> D() {
std::stringstream ss;
ss << "D(" << Rank << ")";
std::array<unsigned int, Rank - 1> mults;
mults.fill(3);
mults[Rank - 2] = 2;
Group<Rank> g = schlafli<Rank>(mults, ss.str());
g(1, Rank - 1) = 3;
return g;
}
/**
* E groups
*/
template<unsigned int Rank>
Group <Rank> E() {
std::stringstream ss;
ss << "E(" << Rank << ")";
std::array<unsigned int, Rank - 1> mults;
mults.fill(3);
mults[Rank - 2] = 2;
Group<Rank> g = schlafli<Rank>(mults, ss.str());
g(2, Rank - 1) = 3;
return g;
}
/**
* 24 Cell
*/
Group<4> F4() {
return schlafli<4>({3, 4, 3}, "F4");
}
/**
* Hexagon
*/
Group<2> G2() {
return schlafli<2>({6}, "G2");
}
/**
* Icosahedron
*/
template<unsigned int Rank>
Group <Rank> H() {
std::stringstream ss;
ss << "H(" << Rank << ")";
std::array<unsigned int, Rank - 1> mults;
mults.fill(3);
mults[0] = 5;
return schlafli<Rank>(mults, ss.str());
}
/**
* Polygonal
*/
Group<2> I2(unsigned int n) {
std::stringstream ss;
ss << "I2(" << n << ")";
return schlafli<2>({n}, ss.str());
}
/**
* Toroidal. I2(n) * I2(m)
*/
Group<4> T(unsigned int n, unsigned int m) {
std::stringstream ss;
ss << "T(" << n << "," << m << ")";
return schlafli<4>({n, 2, m}, ss.str());
}
/**
* Toroidal. T(n, n)
*/
Group<4> T(unsigned int n) {
std::stringstream ss;
ss << "T(" << n << ")";
return schlafli<4>({n, 2, n}, ss.str());
}
return schlafli<4>({n, 2, n}, ss.str());
}
}