while useful these are extremely hard to read functions. I have been having problems with mchgu for vectorised inputs. This appears to be due to the logic choices for high and low arguments not working for vectorised x.
1.0e-21 *[-0.4281 0.0320]
gives the correct answer, where as
1.0e+46 * [5.3505 - 4.4981i 0.0000 -4.9590 ]
is wrong by many many orders of magnitude.
Essentially it works fine for single arguments but not vectors.