How does the matrix product block work?

I am doing ... just simple matrix multiplication in simulink and it does not work. Just by speculation alone, the 2 input signals that go into the product block have the dimension 2 and [2x2] respectively, so I expect the block should output some 2-vector, but it does not. Could somebody help me?

[Paul]

Are you trying to form M*tau where tau is column vector? Or tau*M where tau is row vector?

Answer 1

[Walter Roberson]

The input signal is dimension 2, not 1 x 2 or 2 x 1. You need to pass it through a reshape block https://www.mathworks.com/help/simulink/slref/reshape.html

Answer 2

[Fangjun Jiang]

For the [1 2] Constant block, un-check "Interpret vector parameters as 1-D".

For your Inport block, specify its Port dimensions as [1 2]