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LSSTDESC / descwl-shear-sims

simple simulations for testing weak lensing shear measurement
BSD 3-Clause "New" or "Revised" License
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ENH shear integration tests #143

Closed beckermr closed 3 years ago

beckermr commented 3 years ago

This PR has a start for integration tests for shear recovery.

beckermr commented 3 years ago

@esheldon There is a lot going here I don't follow.

  1. I am seeing a 30% shear bias when putting this sim through coadding and then metadetect. There must be a bug somewhere.
  2. The response to shear in g2 is negative, which is extremely odd.

Can you look through the code?

beckermr commented 3 years ago

OK, I figured out the bias. The stack is shredding objects when the S/N is too high. I was using mag=14 in our units and seeing it not find 36 objects every time. This caused big non-linearities in the response to shear which breaks mdet.

I still think we need to track down the minus sign in R22. I'll make an issue.

beckermr commented 3 years ago

This PR is ready for review!