F# vector rowvector multiplication issue

Question

I need to multiply a Vector by a RowVector to get a Matrix as the result. But the F# libraries do not have such an implementation for the * operator. How can I do this?

//wj(t+1)=wj(t) - a * (yk-dk)* xjk
let weightsDeltaRule (w : matrix, x : vector, y : vector, d : vector) (a : float) = 
    let delta = y - d
    w - a * (Vector.transpose x) * delta

UPD:

vector<'T> *  rowvec<'T> -> matrix<'T>
rowvec<'T> * vector<'T> -> 'T

Answer 1

Why do you think the powerpack doesn't implement Vector * RowVector = Matrix ?

Taken from matrix.fsi

/// Multiply a column vector and a row vector to produce a matrix
static member ( * )   : Vector<'T>    * RowVector<'T> -> Matrix<'T>