Issue with the SRA case in metabolic_sensitivity

[ScottCampit]

Describe the bug
The reduced cost line in metabolic sensitivity returns an output error. The value that I want stored (which in some cases is 0) is returned as an empty array. This causes a size error.

To Reproduce
Run the code as written in the scampit branch

Expected behavior
I would expect that the empty value will be filled in as a 0 if the reduced cost were in fact 0.