public static MathMatrix Identity(int dim)
{
MathMatrix retval = MathMatrix.CreateMatrix(dim, dim, 0);
for (int idx = 0; idx < dim; ++idx)
{
retval[idx, idx] = 1;
}
return(retval);
}
// THE DOMAIN OF THIS FUNCTION AS OF NOW DOES NOT INCLUDE COMPLEX NUMBERS.
public static MathMatrix Sqrt_Elmtwise(MathMatrix A)
{
MathMatrix sqrt = MathMatrix.CreateMatrix(A.RowCount, A.ColCount);
for (int r = 0; r < A.RowCount; ++r)
{
for (int c = 0; c < A.ColCount; ++c)
{
sqrt[r, c] = Math.Sqrt(A[r, c]);
}
}
return(sqrt);
}
public static MathMatrix Transpose(MathMatrix inMatrix)
{
MathMatrix retval = MathMatrix.CreateMatrix(inMatrix.ColCount, inMatrix.RowCount);
for (int m = 0; m < inMatrix.RowCount; ++m)
{
for (int n = 0; n < inMatrix.ColCount; ++n)
{
retval[n, m] = inMatrix[m, n];
}
}
return(retval);
}
public static MathMatrix Normal(int count, double mu = 1, double sigmasq = 0)
{
MathMatrix normalvec = MathMatrix.CreateMatrix(1, count);
for (int idx = 0; idx < count; ++idx)
{
Random rand = new Random();
double u1 = 1.0 - rand.NextDouble();
double u2 = 1.0 - rand.NextDouble();
double randStdNormal = Math.Sqrt(-2.0 * Math.Log(u1)) * Math.Sin(2.0 * Math.PI * u2);
double randNormal = mu + Math.Sqrt(sigmasq) * randStdNormal;
normalvec[0, idx] = randNormal;
}
return(normalvec);
}
public static MathMatrix SteppedSequence(double begin, double end, double step)
{
List <decimal> seq = new List <decimal>();
for (decimal idx = Convert.ToDecimal(begin); idx <= Convert.ToDecimal(end); idx += Convert.ToDecimal(step))
{
seq.Add(idx);
}
MathMatrix retval = MathMatrix.CreateMatrix(1, seq.Count);
for (int idx = 0; idx < seq.Count; ++idx)
{
retval[0, idx] = Convert.ToDouble(seq[idx]);
}
return(retval);
}
public static MathMatrix Subtract(MathMatrix A, MathMatrix B)
{
if (A.RowCount != B.RowCount || A.ColCount != B.ColCount)
{
throw new InvalidMatrixAddDimensionsException();
}
MathMatrix difference = MathMatrix.CreateMatrix(A.RowCount, A.ColCount);
for (int r = 0; r < A.RowCount; ++r)
{
for (int c = 0; c < B.ColCount; ++c)
{
difference[r, c] = A[r, c] - B[r, c];
}
}
return(difference);
}
public static MathMatrix Add(MathMatrix A, MathMatrix B)
{
if (A.RowCount != B.RowCount || A.ColCount != B.ColCount)
{
throw new InvalidMatrixAddDimensionsException();
}
MathMatrix sum = MathMatrix.CreateMatrix(A.RowCount, A.ColCount);
for (int r = 0; r < A.RowCount; ++r)
{
for (int c = 0; c < B.ColCount; ++c)
{
sum[r, c] = A[r, c] + B[r, c];
}
}
return(sum);
}
public static MathMatrix Multiply(MathMatrix A, MathMatrix B)
{
if (A.ColCount != B.RowCount)
{
throw new InvalidMatrixMultiplicationDimensionsException();
}
MathMatrix product = MathMatrix.CreateMatrix(A.RowCount, B.ColCount, 0);
for (int r = 0; r < A.RowCount; ++r)
{
for (int c = 0; c < B.ColCount; ++c)
{
for (int x = 0; x < B.RowCount; ++x)
{
product[r, c] += A[r, x] * B[x, c];
}
}
}
return(product);
}