Why does the Create Diagonal Matrix block produce incorrect results with complex data types in DSP Blockset 5.0 (R13) and later versions?

I obtain incorrect results from the Create Diagonal Matrix block with complex data types in DSP Blockset 5.0 (R13) and later versions.

If I provide the following input vector to the Create Diagonal Matrix block:

 [3; 2; 4]

I receive the correct output matrix and all of the elements off the diagonal are equal to zero. However, if I use a complex number for the first element like so:

 [3i; 2; 4]

the output matrix contains non-zero values for elements off the diagonal.

Is the expected behavior?

Answer 1

[MathWorks Support Team]

We have verified that there is a bug in DSP Blockset 5.0 (R13) and later versions in the way that the Create Diagonal Matrix block handles complex inputs.

To work around this issue, use the MATLAB Fcn block with the MATLAB DIAG function.