/// <summary>
/// Accord.NET
/// Computes the product A*B of matrix <c>A</c> and diagonal matrix <c>B</c>.
/// </summary>
///
/// <param name="a">The left matrix <c>A</c>.</param>
/// <param name="diagonal">The diagonal vector of right matrix <c>B</c>.</param>
/// <param name="result">The matrix <c>R</c> to store the product <c>R = A*B</c>
/// of the given matrices <c>A</c> and <c>B</c>.</param>
///
public static double[,] DotWithDiagonal(this double[,] a, double[] diagonal, double[,] result)
{
#if DEBUG
var C = Dot(a.To <double[, ]>(), MatrixEx.Diagonal(diagonal.To <double[]>()));
#endif
int rows = a.Rows();
unsafe
{
fixed(double *ptrA = a)
fixed(double *ptrR = result)
{
double *A = ptrA;
double *R = ptrR;
for (int i = 0; i < rows; i++)
{
for (int j = 0; j < diagonal.Length; j++)
{
*R++ = (double)((double)(*A++) * (double)diagonal[j]);
}
}
}
}
#if DEBUG
if (!MatrixEx.IsEqual(C, result.To <double[, ]>(), 1e-4))
{
throw new Exception();
}
#endif
return(result);
}
