We are looking to plot to time series accelerometer data as velocity and displacement. To this end we tried scipy.fftpack.diff, but in looking at the test code direct_diff() we get odd results, and, why is the doc using "sqrt(-1)*j" in its explanation? So, I tried a few different integration methods. We were first looking at the doc at http://docs.scipy.org/doc/scipy-0.15.1/reference/generated/scipy.fftpack.dif... and code at https://github.com/scipy/scipy/blob/v0.15.1/scipy/fftpack/pseudo_diffs.py#L2... as well as the tests at https://github.com/scipy/scipy/blob/master/benchmarks/benchmarks/fftpack_pse... The direct_diff() test function in bench_pseudo_diffs.py seems odd, since I have to pass period=-1 to get a matching sign plot for the first integration. And why the scaling differences required, even for diff() and direct_diff()? Is my understanding fundamentally flawed? Emacs! Ray
