public static Vector operator *(Vector v, Matrix m)
{
Contract.Requires(v != null);
Contract.Requires(m != null);
LowerTriangEtaMatrix ltr = m as LowerTriangEtaMatrix;
if (ltr != null)
{
return(v * ltr);
}
TranspositionMatrix tr = m as TranspositionMatrix;
if (tr != null)
{
return(v * tr);
}
Contract.Assume(v.Length == m.NumberOfRows);
Vector r = new Vector(m.NumberOfColumns);
for (int i = 0; i < m.NumberOfColumns; i++)
{
double s = 0;
for (int j = 0; j < v.Length; j++)
{
s += v[j] * m[j, i];
}
r[i] = s;
}
return(r);
}
static public double[] operator *(Matrix b, double[] a)
{
Contract.Requires(b != null);
Contract.Requires(a != null);
Contract.Ensures(Contract.Result <double[]>() != null);
LowerTriangEtaMatrix L = b as LowerTriangEtaMatrix;
if (L != null)
{
return(L * a);
}
TranspositionMatrix P = b as TranspositionMatrix;
if (P != null)
{
return(P * a);
}
throw new NotImplementedException();
}
/// <summary>
/// If one parameter is a Vector then it can be reused for the answer
/// </summary>
/// <param name="a"></param>
/// <param name="b"></param>
/// <returns></returns>
static public Matrix operator *(Matrix a, Matrix b)
{
Contract.Requires(a != null);
Contract.Requires(b != null);
Contract.Requires(a.NumberOfRows > 0);
Vector v = b as Vector;
if (v != null)
{
Contract.Assume(a.NumberOfColumns == v.Length);
TranspositionMatrix transposition = a as TranspositionMatrix;
if (transposition != null)
{
return(v * transposition);
}
else
{
LowerTriangEtaMatrix lm = a as LowerTriangEtaMatrix;
if (lm != null)
{
return(lm * v);
}
else
{
double[] cfs = new double[a.NumberOfRows];
for (int i = 0; i < a.NumberOfRows; i++)
{
double r = 0;
for (int j = 0; j < v.Length; j++)
{
r += a[i, j] * v[j];
}
cfs[i] = r;
}
return(new Vector(cfs));
}
}
}
else
{
v = a as Vector;
if (v != null)
{
return(v * b);
}
else
{
Contract.Assert(a.NumberOfRows > 0);
Contract.Assume(a.NumberOfColumns == b.NumberOfRows);
FullMatrix ret = new FullMatrix(a.NumberOfRows, new double[a.NumberOfRows * b.NumberOfColumns]);
for (int i = 0; i < a.NumberOfRows; i++)
{
for (int j = 0; j < b.NumberOfColumns; j++)
{
double r = 0;
for (int k = 0; k < a.NumberOfColumns; k++)
{
r += a[i, k] * b[k, j];
}
Contract.Assume(b.NumberOfColumns <= ret.NumberOfColumns); // F: Cannot prove it because quadratic
ret[i, j] = r;
}
}
return(ret);
}
}
}
