public static Array <Real> TensorDotRight(this Array <Real> mat, Array <Real> vec, Array <Real> result = null, Real beta = 1)
{
if (vec.Shape.Length != 1)
{
throw new ArgumentException();
}
if (mat.Shape.Length != 2)
{
throw new ArgumentException();
}
var shape = new[] { mat.Shape[0], mat.Shape[1], vec.Shape[0] };
if (result == null)
{
result = new Array <Real>(shape);
}
else if (result.Shape.Length != shape.Length)
{
throw new ArgumentException(); // TODO: check axes
}
var offsetRes = result.Offset;
for (int i = 0; i < vec.Shape[0]; ++i)
{
// result[_, _, i] = vec[i] * mat + beta * result[_, _, i]
if (beta != 1)
{
Blas.scal(mat.Size, beta, mat.Values, offsetRes, mat.Stride[1]);
}
Blas.axpy(mat.Size, vec.Item[i], mat.Values, mat.Offset, mat.Stride[1], result.Values, offsetRes, result.Stride[1]);
offsetRes += result.Stride[2];
}
return(result);
}
public static Array <Real> Scale(this Array <Real> a, Real alpha, Array <Real> result = null)
{
if (result != a)
{
result = a.Copy(result: result);
}
Array_.ElementwiseOp(0, result, 0, (n, x, offsetx, incx) => { Blas.scal(n, alpha, x, offsetx, incx); });
return(result);
}
