Error: should not happen (3,1)

[GrantChandler]

I'm getting an error that I can't figure out at all. I'm trying to invert a 4x4 matrix. All of the terms in the matrix are 3x3 matrices except for the m's are constants; hence, a 12x12 matrix.

[RichardJ]

Which version of Mathcad (including service releases)?

Please also post the worksheet that shows the problem.

[GrantChandler]

Mathcad 14.0 M020 (14.0.2.5 [802141434])

[GrantChandler]

It seems like the problem might stem from nesting the matrices and then trying to take the invese as if a 12x12 matrix. I've upload my sheet. Culprit is on the bottom of the 3rd page.

Also, a simpler version illustraiting the point is attached.

[MikeArmstrong]

Something like the attached.

Mike

[RichardJ]

Sorry. I should have read your original post more carefully. I got distracted by the weird error message

You have a nested matrix. That does not translate into a larger matrix. It is exactly what it appears to be, a matrix of matrices, and you cannot invert that.

[MikeArmstrong]

I got distracted by the weird error message

Come on, we don't still get wierd error messages do we?

Mike