Why am I getting a wrong matrix inverse when using a Math Function block set to 'pow' in Simulink?

I want to calculate a matrix inverse in Simulink. For example, for matrix A = [4 0; 0 16]. I am using a Math Function block set to 'pow' to do the inverse. However, I get erroneous result as below:

A^-1 = [0.25 inf; inf 0.0625]

rather than

A^-1 = [0.25 0; 0 0.0625]

Answer 1

[MathWorks Support Team]

Using the Math Function block set to 'pow' to do the inverse operation does the element-wise inverse rather than inverting the whole matrix. To carry out a matrix inverse, please follow the steps below:

1. Add a Product block into the model
2. Double click on the block
3. Under 'Number of inputs' section replace the number '2' with the right-matrix division symbol ' / '
4. Select 'Multiplication' as 'Matrix(*)'

This will return the matrix inverse.