internal static void SubFrom(ref MxMatrix from, MxMatrix subtractor, int dim)
{
for (var i = 0; i < dim * dim; i++)
{
from[i] -= subtractor[i];
}
}
internal bool Jacobi(MxMatrix input, ref double[] eigenValues, ref double[] eigenVectors)
{
var a = new[] { new double[3], new double[3], new double[3] };
var v = new[] { new double[3], new double[3], new double[3] };
for (var i = 0; i < 3; i++)
{
for (var j = 0; j < 3; j++)
{
a[i][j] = input[i, j];
}
}
var result = InternalJacobi(a, ref eigenValues, ref v);
if (!result)
{
return(false);
}
var index = 0;
for (var i = 0; i < 3; i++)
{
for (var j = 0; j < 3; j++)
{
eigenVectors[index++] = v[j][i];
}
}
return(true);
}
internal static void AddInto(ref MxMatrix into, MxMatrix addend, int dim)
{
for (var i = 0; i < dim * dim; i++)
{
into[i] += addend[i];
}
}
internal static void Scale(ref MxMatrix mat, double scalar, int dim)
{
for (var i = 0; i < dim * dim; i++)
{
mat[i] *= scalar;
}
}
internal static void InvScale(ref MxMatrix mat, double scalar, int dim)
{
var invScale = 1.0 / scalar;
for (var i = 0; i < dim * dim; i++)
{
mat[i] *= invScale;
}
}
internal MxMatrix(MxMatrix mat)
: base(mat.Dim, mat.Dim)
{
Copy(mat);
}
private static double InternalInvert(MxMatrix matA, ref MxMatrix matInvA)
{
var dim = matA.Dim;
int i, j = 0, k;
double max, t, det, pivot;
//Initialize the inverse matrix as the Identity matrix
for (i = 0; i < dim; i++)
{
for (j = 0; j < dim; j++)
{
matInvA[i, j] = ((i == j) ? 1.0 : 0.0);
}
}
det = 1.0;
// eliminate in column i, below the diagonal
for (i = 0; i < dim; i++)
{
max = -1.0;
for (k = i; k < dim; k++)
{
var abs = Math.Abs(matA[k, i]);
if (abs <= max)
{
continue;
}
max = abs;
j = k;
}
if (max <= 0.0)
{
return(0.0);
}
if (j != i)
{
for (k = i; k < dim; k++)
{
t = matA[i, k];
matA[i, k] = matA[j, k];
matA[j, k] = t;
}
for (k = 0; k < dim; k++)
{
t = matInvA[i, k];
matInvA[i, k] = matInvA[j, k];
matInvA[j, k] = t;
}
det = -det;
}
pivot = matA[i, i];
det *= pivot;
for (k = i + 1; k < dim; k++)
{
matA[i, k] /= pivot;
}
for (k = 0; k < dim; k++)
{
matInvA[i, k] /= pivot;
}
for (j = i + 1; j < dim; j++)
{
t = matA[j, i];
for (k = i + 1; k < dim; k++)
{
matA[j, k] -= matA[i, k] * t;
}
for (k = 0; k < dim; k++)
{
matInvA[j, k] -= matInvA[i, k] * t;
}
}
}
for (i = (dim - 1); i > 0; i--)
{
for (j = 0; j < i; j++)
{
t = matA[j, i];
for (k = 0; k < dim; k++)
{
matInvA[j, k] -= matInvA[i, k] * t;
}
}
}
return(det);
}
internal static double Invert(MxMatrix matA, MxMatrix matInvA)
{
var a2 = new MxMatrix(matInvA);
return(InternalInvert(matA, ref a2));
}
