// ----------------------------------------------------------------
tmatrix<f2polymod_t> f2np_companion_matrix(
f2npoly_t chpol)
{
int n = chpol.find_degree();
f2poly_t m = chpol.get_coeff(0).get_modulus();
f2poly_t zero(0);
f2poly_t one(1);
f2polymod_t zero_m(zero, m);
f2polymod_t one_m(one, m);
tmatrix<f2polymod_t> rv(n, n);
int i;
// chpol = 10011
// 0 0 1 1
// 1 0 0 0
// 0 1 0 0
// 0 0 1 0
rv = zero_m;
for (i = 1; i < n; i++)
rv[i][i-1] = one_m;
for (i = 0; i < n; i++)
rv[0][n-1-i] = -chpol.get_coeff(i);
return rv;
}
inline
void
matrix_perspective_lh( T (&r)[4][4], T fov_y, T aspect_ratio, T zn, T zf )
{
T ys=T(1)/::tanf(fov_y/T(2));
T xs=ys/aspect_ratio;
zero_m(r);
r[0][0] = xs;
r[1][1] = ys;
r[2][2] = zf/(zf-zn);
r[2][3] = -zn*zf/(zf-zn);
r[3][2] = 1;
}
