any util function for a Matrix X a float64?

[Letitgo]

otherwise, I have to do this:

// matrix m * float64 a
func mulMatrixVar(m *mat64.Dense, a float64) (*mat64.Dense) {
        mm, nn := m.Dims()
        arr := make([]float64, mm*nn)

        for i := 0; i < mm; i++ {
                for j := 0; j < nn; j++ {
                        arr[i*mm + j] = a * m.At(i, j)
                }
        }
        return mat64.NewDense(mm, nn, arr)
}

[Dan Kortschak]

*mat64.Dense is a mat64.Scaler. If you want it in pace, just call Scale. If you want it not in place clone the matrix first.

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[Letitgo]

thank you!

m.Scale(2, m)
it works.

On Saturday, July 11, 2015 at 5:37:55 PM UTC-7, kortschak wrote:

*mat64.Dense is a mat64.Scaler. If you want it in pace, just call Scale. If you want it not in place clone the matrix first.

On 12/07/2015, at 10:01 AM, "Letitgo" <mars....@gmail.com> wrote:

otherwise, I have to do this:

// matrix m * float64 a
func mulMatrixVar(m *mat64.Dense, a float64) (*mat64.Dense) {
        mm, nn := m.Dims()
        arr := make([]float64, mm*nn)

        for i := 0; i < mm; i++ {
                for j := 0; j < nn; j++ {
                        arr[i*mm + j] = a * m.At(i, j)

a typo here, it's i*nn+j
 

[Dan Kortschak]

BTW, your original approach is not correct for all matrices since it assumes cols==stride.

[Dan Kortschak]

Also, my first claim about non-inplace is wrong - you can just use a zero matrix as the receiver and not do a clone.