Inconsistency in results between MacOS and Ubuntu about namaster

[gfabbian]

I am seeing the same thing for M3 chips and independently found analogous (or worse results). I did try set input E-modes to 0 but still recover crazy B-modes spectra regardless. In the attached plot an example of the result, where theory in the error bar is the usual Gaussian "fsky-approximated" error bar.
Note that problem also affects E-modes even if only B-modes are purified.

For reference, also compiling from source didn't fix the problem so it is probably not a conda package problem.

[damonge]

Could you try installing the latest version currently on conda (v2)? I'm hoping that any issues with the new Mac chips are now gone.

[gfabbian]

Sadly I'm seeing consistent results even with V2 (the variance is slightly worse)

[damonge]

OK, thanks a lot.

The fact that this still happens with the newer version narrows it down, I think. Most of the code is completely different, so this can only be coming from a couple of things. I'm trying to test this on my own without a mac, but in the meantime, can I check:

• Does this only happen with purification, and otherwise the code works as expected?
• If the answer above is yes, can you check if the two apodised masks (generated in linux or mac) are the same?

[damonge]

@fjaviersanchez is not able to reproduce this with a fresh install from conda. His setup is:

• M2 chip

• healpy version: '1.16.6' , numpy version: '1.26.4', pymaster version: 2.0

@gfabbian can I check how this differs from yours?

[damonge]

(also, just to check, you are indeed installing from conda, correct?)

[fjaviersanchez]

For more context, this is the recipe I followed to install the package:

conda create -n namaster2 namaster -c conda-forge
conda activate namaster2
conda install healpy -c conda-forge

I can play a bit with the numpy and healpy versions to see if those are responsible.

[gfabbian]

@fjaviersanchez are you using conda with osx-arm64 platform or osx-64?

I have the same numpy/healpy as yours and see the issue even when creating a new environment :(. I also confirm issues show up in purification. Happy to rerun any test code you have. I can also send out a notebook if useful.

[fjaviersanchez]

Hmm, I just checked and this is my conda info:

platform : osx-arm64

I am using python 3.12. I haven't checked with 3.11 though, and I know that some people had issues with 3.11 with other packages. I can check!

[gfabbian]

I believe the only thing different at this point is the chip as I also have python 3.12.

[damonge]

Humm, but @jchamilton75 said he was using an M2 above...

[gfabbian]

@jchamilton75 can you confirm if you see the problem with a fresh environment installation?

[damonge]

After further offline iterations with @gfabbian (thanks so much for this @gfabbian ), it seems the issue was conflicting old versions of ducc0 installed via pip. When installing all packages consistently from conda the problem disappears (@gfabbian please correct me if what I just said is inaccurate).

I'll close this for now, but feel free to reopen if the issue reappears.