Re: unwanted randomness while generating LilyPond output

[Carl Sorensen]

On Mon, Feb 19, 2024 at 1:28 PM Michael Käppler <xmichael-k@web.de> wrote:

> Hello Werner,
> thanks for your reply!
>
> Just to make sure we're on the same page: You don't assume that there is
> variability across
> different runs of the same LilyPond build on the same machine? (Aka some
> kind of "non-deterministic behaviour")
> That would be my understanding of "randomness", which I find a bit of a
> misleading term here.
>

I don't think that we have any evidence that different runs on the same
machine produce different output.

As far as I know, we only  have evidence that Werner's computer produced a
different file than my computer when we were both using the same commit of
LilyPond (but we have different operating systems, and different versions
of all of the OS tools).


> FWIW, I can confirm that 100 subsequent runs of `lilypond --eps
> input.ly` on my machine
> produce exactly bit-identical eps files.
>
> Carl and Werner, could you please:
>
> * patch scm/framework-ps.scm with the attached patch (go to the
> directory where framework-ps.scm resides
> and run `patch < epsdebug.patch`)
>

I will try to make this happen tomorrow.


>
> (Does not have to be in the source tree, you can also do a backup of
> framework-ps.scm and patch your working installation)
>
> This patch will print the page stencils as pretty-printed scheme code to
> stdout, while
> normal messages go to stderr.
>
> * run `lilypond --eps input.ly > epsdebug.log`
>
> * send me the resulting log files
>

Carl