/* Copyright (C) 2011 Fredrik Johansson This file is part of FLINT. FLINT is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License (LGPL) as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. See . */ #include #include "flint.h" #include "fmpz_poly.h" #include "fmpz_poly_mat.h" void fmpz_poly_mat_pow(fmpz_poly_mat_t B, const fmpz_poly_mat_t A, ulong exp) { slong d = fmpz_poly_mat_nrows(A); if (exp == 0 || d == 0) { fmpz_poly_mat_one(B); } else if (exp == 1) { fmpz_poly_mat_set(B, A); } else if (exp == 2) { fmpz_poly_mat_sqr(B, A); } else if (d == 1) { fmpz_poly_pow(fmpz_poly_mat_entry(B, 0, 0), fmpz_poly_mat_entry(A, 0, 0), exp); } else { fmpz_poly_mat_t T, U; slong i; fmpz_poly_mat_init_set(T, A); fmpz_poly_mat_init(U, d, d); for (i = ((slong) FLINT_BIT_COUNT(exp)) - 2; i >= 0; i--) { fmpz_poly_mat_sqr(U, T); if (exp & (WORD(1) << i)) fmpz_poly_mat_mul(T, U, A); else fmpz_poly_mat_swap(T, U); } fmpz_poly_mat_swap(B, T); fmpz_poly_mat_clear(T); fmpz_poly_mat_clear(U); } }