public ModMatrix(ModMatrix mat)
{
Dimension = mat.Dimension;
Modulus = mat.Modulus;
m = new BigInteger[Dimension, Dimension];
for (int y = 0; y < Dimension; y++)
{
for (int x = 0; x < Dimension; x++)
{
m[x, y] = mat[x, y];
}
}
}
public ModMatrix invert()
{
ModMatrix mi = new ModMatrix(Dimension, Modulus);
BigInteger di = BigIntegerHelper.ModInverse(det(), Modulus);
for (int y = 0; y < Dimension; y++)
{
for (int x = 0; x < Dimension; x++)
{
int sign = 1 - 2 * ((x + y) % 2); // sign = (-1) ^ (x+y)
mi[x, y] = (((sign * di * minor(y, x)) % Modulus) + Modulus) % Modulus;
}
}
return(mi);
}
public static ModMatrix operator *(ModMatrix matA, ModMatrix matB)
{
ModMatrix result = new ModMatrix(matA.Dimension, matA.Modulus);
for (int y = 0; y < result.Dimension; y++)
{
for (int x = 0; x < result.Dimension; x++)
{
result[x, y] = 0;
for (int i = 0; i < result.Dimension; i++)
{
result[x, y] += matA[i, y] * matB[x, i];
result[x, y] = ((result[x, y] % result.Modulus) + result.Modulus) % result.Modulus;
}
}
}
return(result);
}
public ModMatrix submatrix(int x, int y)
{
ModMatrix submatrix = new ModMatrix(Dimension - 1, Modulus);
for (int xx = 0, xi = 0; xx < Dimension; xx++)
{
if (xx == x)
{
continue;
}
for (int yy = 0, yi = 0; yy < Dimension; yy++)
{
if (yy == y)
{
continue;
}
submatrix[xi, yi] = m[xx, yy];
yi++;
}
xi++;
}
return(submatrix);
}
