[Pkg-octave-devel] Get octave-communications to build reproducibly

[Oliver Heimlich]

On 26.07.2016 20:33, Rafael Laboissière wrote:
> I am trying to have the octave-communications package building
> reproducibly [1].  I followed the instructions in the wiki page [2] and
> did the commit 3b602b6 [3].  However, the package still does not build
> reproducibly. Does anyone know how to do it?

Since the differences are in the manual I suspected the images generated
for the manual. There are three images that get generated for the manual
using doc/commsimages.m: awgn, eyediagram, and scatterplot.

- awgn uses random numbers, but seeds them with randn ("state", 10), so
this should be reproducible.

- eyediagram and scatterplot use the function randsrc without a 4th seed
parameter. The randsrc function uses the rand function internally, which
uses a different RNG state compared to randn. So this probably is the
reason.

I'd suggest to change the following line in commsimages.m and add a
forth seed parameter for both instances.

    y = randsrc (1, n, [1 + 1i, 1 - 1i, -1 - 1i, -1 + 1i]);

Oliver