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epic-astronomy / LWA_EPIC

The LWA-specific implementation of the EPIC correlator
http://livetv.epic-astronomy.org
MIT License
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Is DFT code deterministic? #13

Closed mkolopanis closed 4 years ago

mkolopanis commented 4 years ago

I ran the DFT code twice from commit f22d93364ebda98ab476483fc95f7bcac6019696 in offline and received differing results from both runs. This is troubling considering the input should have been identical.

command used:

python LWA_bifrost_DFT.py --offline --tbnfile=/data5/LWA_SV_data/data_raw/TBN/Jupiter/058161_000086727 --imagesize 64 --imageres 1.79057 --nts 512 --channels 4 --accumulate 50 --ints_per_file 40 --out_dir dft/run_?

See attached jupyter notebook output for more information. dft_comparison.pdf

adampbeardsley commented 4 years ago

This sounds a lot like the bug we fixed in #4. Maybe check that the synchronization lines we added are in fact still there and didn't get bulldozed by a merge at some point? https://github.com/epic-astronomy/LWA_EPIC/pull/4/files

mkolopanis commented 4 years ago

thanks for this. I'll take a look.

mkolopanis commented 4 years ago

I will implement this in my script_consolidation branch. Looks like I already did :laughing:
the two runs are identical at least on commit f7a59d37a7ff8d5fba7bac4eb464f2b66cda77ac dft_comparison_update.pdf