Chain linking matrix multiplication function

[toadhall]

Hi,
I have 30 different matrices and I want a function that chain links them by multiplication. To do this with MMult quickly becomes a very long formula.

I have already a matrix power function which raises a particular matrix to a certain power, n

Function MPower(Matrix, n)
    If n = 1 Then
        MPower = Matrix
        Else: MPower = Application.MMult(MPower(Matrix, n - 1), Matrix)
    End If
End Function

Now I need a similar function that multiplies different matrices together

I.e. Matrix 1 x Matrix 2 x Matrix 3....Matrix n

so
if n=3, then the function returns Matrix 1 x Marrix 2 x Matrix 3.
if n=2, function returns Matrix 1 x Matrix 2 etc

Can anyone help?
thanks
toby

[lecxe]

Hi toby

I hope this will get you started.

The code has no error checking, you can add it. I assumed you use it with at least 2 matrices, the dimensions of the matrices are correct, etc.

You can use for ex. like this:

=MMultN(B3:C4,E3:G4,I3:J5)

Function MMultN(ParamArray vMatrices() As Variant) As Variant
Dim j As Long

MMultN = Application.MMult(vMatrices(0), vMatrices(1))
For j = 2 To UBound(vMatrices)
    MMultN = Application.MMult(MMultN, vMatrices(j))
Next j
End Function

[toadhall]

thats great
thanks