multifit_solver example broken: covariance matrix must be square and match second dimension of jacobian

[guillaumegomez]

multifit_solver example broken: covariance matrix must be square and match second dimension of jacobian

@GuillaumeGomez Did you solve this issue? I have the same problem with the example as well. And the optimization seems weird as well. It only run one iteration and then exit.

[hombit]

@SebastianSchafer see #82, we have UB here because of inconsistent binding with GSL 2.x

[SuperFluffy]

This is what happens when printing covar and s.J() right before the call to rgsl::multifit::covar(&s.J(), 0f64, &mut covar):

covar: [0, 0, 0]
[0, 0, 0]
[0, 0, 0]
s.J(): [0.000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000015]
zsh: segmentation fault (core dumped)  cargo run --example multifit_solver

Segfault on J.

[GuillaumeGomez]

That's surprising... I'll have to take a look and see what's failing.

[SuperFluffy]

In case it's relevant, I am on Arch Linux using gsl 2.5.

I also encountered an error with integration:

./integration
=== integration::qng ===
Result 1.8390715290764525 +/- 0.000000000009921183292055902 from 21 evaluations

=== IntegrationWorkspace.qag ===
gsl: src/types/integration.rs:3430: ERROR: a maximum of one iteration was insufficient
Default GSL error handler invoked.
zsh: abort (core dumped)  ./integration

[GuillaumeGomez]

That's getting weirder and weirder...

[GuillaumeGomez]

I can't reproduce the error so I can't solve it... :-/

@GuillaumeGomez What is the version of gsl are you using? I am using gsl 2.4. Is that old? I saw the newest version is 2.6.

[GuillaumeGomez]

I removed GSL libs last time so I can't tell. Maybe it changed in the meantime in the repositories... If I have time and motivation, I'll try to take a look.

cool, thank you for your response

[GuillaumeGomez]

Don't hesitate to ping me in a month or so if you see no changes here. :)

[hombit]

Same problem here. The first, it makes only one iteration, because s.dx() is all zeros (but s.x() changes during the only iteration). The second, I see the same error about covariant matrix.

I use macOS and GSL 2.6.

[hombit]

Also I can reproduce it in rust Docker container (GSL 2.5) both on AMD64 and ARM64:

docker run --rm -ti rust:buster
apt update && apt install -y libgsl-dev
git clone https://github.com/GuillaumeGomez/rust-GSL && cd rust-GSL
cargo run --example multifit_solver

[SebastianSchafer]

Can reproduce this also on Ubuntu 20.04 & GSL 2.5. That is, the s.iterate() loop stops after first iteration and dimensitons mismatch. I don't see any segfault error as described by SuperFluffy. For this example, J turns out to be 3x1 but GSL expects 1x3 I guess. While finishing during the first iteration as others described seems suspect, that shouldn't affect the shape of J, so we might be looking at more than one issue?