internal double[,] GetBestMatrix(int f0, double[] p0, int f1, double[] p1)
{
// move from (f0,p0) to (f1,p1); point p is on the cell surface.
PFace F0 = Faces[f0], F1 = Faces[f1];
if (F0.Base.Id != F1.Base.Id)
{
return(null);
}
double[] q0 = PGeom.ApplyInvMatrix(F0.Matrix, p0);
double[] q1 = PGeom.ApplyInvMatrix(F1.Matrix, p1);
double dbest = double.MaxValue;
double[,] mr = null;
foreach (double[,] m in F0.Base.SMatrices)
{
double[] qq = PGeom.ApplyMatrix(m, q0);
double v = PGeom.Dist2(qq, q1);
if (v < dbest)
{
dbest = v; mr = m;
}
}
return(PGeom.MatrixMulInv2(F0.Matrix, PGeom.MatrixMul(mr, F1.Matrix)));
}
