Rune wrote:
> 
> I have a matrix A. Then I transform it by the matrix B. The result is Matrix
> C. Given A and C, how do I find B ?

[A][B] = [C]

Premultiply both sides by the inverse of [A]

[A-1][A][B] = [A-1][C]

a matrix times its inverse is the indentity matrix, hence

[1][B] = [A-1][C]

any matrix times the identity matrix is the matrix itself, hence

[B] = [A-1][C]

Q.E.D.

However, this only works for square matrices (if my math isn't too
rusty).

> 
> Instead of matrixes the input and output should be sets of 4 vectors each.
> 
> I imagine a macro like this:
> 
> FindMatrix (Ax,Ay,Az,Ap,Cx,Cy,Cz,Cp)
> 
> It would #declare the vectors Bx, By, Bz and Bp

The macro coding is left to the student as an exercice. :)

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