HELP needed with VBA MMULT

[mattchew]

Hi guys,

I'm a total newbie and am trying to use mmult in VBA..
All i want to do is multiply 2 matrices (3x3 and 3x1), so that I can use that matrix for more complicated calculations.

Need help on a UDF that returns the final result as a matrix (i.e. 3x1 matrix)

Function matt()
Dim P(1 To 3, 3)
P(1, 1) = 1
P(1, 2) = 2
P(1, 3) = 3
P(2, 1) = 4
P(2, 2) = 5
P(2, 3) = 6
P(3, 1) = 7
P(3, 2) = 8
P(3, 3) = 9


Dim Q(1 To 3, 1)
Q(1, 1) = -1
Q(2, 1) = -2
Q(3, 1) = -3

Dim result(1 To 3, 1)
result = Application.WorksheetFunction.MMult(P, Q)
matt = result
End Function


Thanks in advance!!!

Matt

 

[FastExcel]

Try this

Function matt() As Variant
Dim P(1 To 3, 1 To 3)
P(1, 1) = 1
P(1, 2) = 2
P(1, 3) = 3
P(2, 1) = 4
P(2, 2) = 5
P(2, 3) = 6
P(3, 1) = 7
P(3, 2) = 8
P(3, 3) = 9

Dim Q(1 To 3, 1 To 1)
Q(1, 1) = -1
Q(2, 1) = -2
Q(3, 1) = -3

matt = Application.WorksheetFunction.MMult(P, Q)
End Function

 

[hiker95]

mattchew,

Cross posted here:
http://www.ozgrid.com/forum/showthread.php?t=152684

 

[shg]

Another way to initialize variables:

Function matt() As Variant
    Dim P           As Variant
    Dim Q           As Variant
 
    P = Evaluate("{1,2,3;4,5,6;7,8,9}")
    Q = Evaluate("{-1;-2;-3}")
    matt = WorksheetFunction.MMult(P, Q)
End Function