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  1. Data Management
  2. DM-6124

Testing ngmix Psf plugin with CModel

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    Details

    • Type: Story
    • Status: Done
    • Resolution: Done
    • Fix Version/s: None
    • Component/s: meas_extensions_ngmix
    • Labels:
      None
    • Story Points:
      6
    • Epic Link:
    • Sprint:
      DRP X16-3
    • Team:
      Data Release Production

      Description

      Test that the ngmix PSF approx plugin works correctly in our measurement framework by testing it with CModel and comparing results with those produced with ShapeletPsfApprox.

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            Hide
            pgee Perry Gee added a comment -

            This is a comparison of the Gaussian fitters using their default settings. This was just a sanity test. But I did find the omission of the Jacobian because of strange problems with EMPsfApprox doing these simple tests.

            nGauss1: ngmix EMPsfApprox, nGauss = 1
            nGauss2: ngmix EMPsfApprox, nGauss = 2
            SingleGaussian: PsfShapeletApprox
            DoubleGaussian: PsfShapeletApprox

            Models running on a Single Gaussian:
            component 0: amp = 1.000000, sigma = 4.000000

            Using model nGauss1
            DIFFS: (-0.00015829129176376792, 0.0011888552335592665)
            PSF: (ixx=15.9990375642, iyy=15.9990375678, ixy=-1.59644452847e-08),
            (-5.7088e-13, 7.2717e-14))
            [ 0.27003514]

            Using model SingleGaussian
            DIFFS: (-0.00015541221422079763, 0.0012018456926277991)
            PSF: (ixx=15.9999987904, iyy=15.9999994105, ixy=-2.88753774136e-07),
            (7.0562e-10, 5.9369e-10))
            [ 0.28209478]

            Using model nGauss2
            DIFFS: (-0.00015828218642075919, 0.0011889808463263511)
            PSF: (ixx=15.437239682, iyy=15.4376494832, ixy=-0.000212610070082),
            (0.0019808, -0.0022363))
            [ 0.15543501]
            PSF: (ixx=16.7722790887, iyy=16.7717162863, ixy=0.000298129770636),
            (-0.0027039, 0.003053))
            [ 0.11461417]

            Using model DoubleGaussian
            DIFFS: (-0.0001554122121517216, 0.0012018456811670592)
            PSF: (ixx=15.9999999845, iyy=16.0000010528, ixy=-2.86920951877e-07),
            (1.1837e-09, 9.7758e-10))
            [ 0.28209478]
            PSF: (ixx=63.9982986901, iyy=63.9982986901, ixy=1.49369523773e-12),
            (-1.9056e-17, -2.3531e-17))
            [ 1.48330137e-08]

            -------------------------------------
            -------------------------------------
            Models running on a double gaussian
            component 0: amp = 1.000000, sigma = 4.000000
            component 1: amp = 0.500000, sigma = 8.000000

            Using model nGauss1
            DIFFS: (-0.00016236985259901842, 0.00093493041720977275)
            PSF: (ixx=26.4048038208, iyy=26.4048038208, ixy=-8.42381887074e-13),
            (-3.7257e-16, -6.1202e-19))
            [ 0.26343557]

            Using model SingleGaussian
            DIFFS: (-0.00016284465841898458, 0.00095982776760274104)
            PSF: (ixx=20.3547972164, iyy=20.2284155693, ixy=0.0631870250436),
            (-0.00017337, -9.5825e-05))
            [ 0.25573096]

            Using model nGauss2
            DIFFS: (-0.0001595243252360783, 0.00095397063580048111)
            PSF: (ixx=15.9668132914, iyy=15.9668132914, ixy=0.0),
            (3.8047e-16, -5.4508e-17))
            [ 0.18150405]
            PSF: (ixx=63.7248239325, iyy=63.7248239325, ixy=-3.79858632292e-16),
            (2.0634e-16, 2.0936e-17))
            [ 0.09142004]

            Using model DoubleGaussian
            DIFFS: (-0.0001572490117598259, 0.0009619403876283553)
            PSF: (ixx=16.169975098, iyy=16.1699215778, ixy=-1.24287220881e-05),
            (7.8807e-07, 2.8255e-06))
            [ 0.19159612]
            PSF: (ixx=67.2220132981, iyy=67.2225928636, ixy=0.000126914960634),
            (2.2892e-07, 4.0119e-07))
            [ 0.09126995]

            Show
            pgee Perry Gee added a comment - This is a comparison of the Gaussian fitters using their default settings. This was just a sanity test. But I did find the omission of the Jacobian because of strange problems with EMPsfApprox doing these simple tests. nGauss1: ngmix EMPsfApprox, nGauss = 1 nGauss2: ngmix EMPsfApprox, nGauss = 2 SingleGaussian: PsfShapeletApprox DoubleGaussian: PsfShapeletApprox Models running on a Single Gaussian: component 0: amp = 1.000000, sigma = 4.000000 Using model nGauss1 DIFFS: (-0.00015829129176376792, 0.0011888552335592665) PSF: (ixx=15.9990375642, iyy=15.9990375678, ixy=-1.59644452847e-08), (-5.7088e-13, 7.2717e-14)) [ 0.27003514] Using model SingleGaussian DIFFS: (-0.00015541221422079763, 0.0012018456926277991) PSF: (ixx=15.9999987904, iyy=15.9999994105, ixy=-2.88753774136e-07), (7.0562e-10, 5.9369e-10)) [ 0.28209478] Using model nGauss2 DIFFS: (-0.00015828218642075919, 0.0011889808463263511) PSF: (ixx=15.437239682, iyy=15.4376494832, ixy=-0.000212610070082), (0.0019808, -0.0022363)) [ 0.15543501] PSF: (ixx=16.7722790887, iyy=16.7717162863, ixy=0.000298129770636), (-0.0027039, 0.003053)) [ 0.11461417] Using model DoubleGaussian DIFFS: (-0.0001554122121517216, 0.0012018456811670592) PSF: (ixx=15.9999999845, iyy=16.0000010528, ixy=-2.86920951877e-07), (1.1837e-09, 9.7758e-10)) [ 0.28209478] PSF: (ixx=63.9982986901, iyy=63.9982986901, ixy=1.49369523773e-12), (-1.9056e-17, -2.3531e-17)) [ 1.48330137e-08] ------------------------------------- ------------------------------------- Models running on a double gaussian component 0: amp = 1.000000, sigma = 4.000000 component 1: amp = 0.500000, sigma = 8.000000 Using model nGauss1 DIFFS: (-0.00016236985259901842, 0.00093493041720977275) PSF: (ixx=26.4048038208, iyy=26.4048038208, ixy=-8.42381887074e-13), (-3.7257e-16, -6.1202e-19)) [ 0.26343557] Using model SingleGaussian DIFFS: (-0.00016284465841898458, 0.00095982776760274104) PSF: (ixx=20.3547972164, iyy=20.2284155693, ixy=0.0631870250436), (-0.00017337, -9.5825e-05)) [ 0.25573096] Using model nGauss2 DIFFS: (-0.0001595243252360783, 0.00095397063580048111) PSF: (ixx=15.9668132914, iyy=15.9668132914, ixy=0.0), (3.8047e-16, -5.4508e-17)) [ 0.18150405] PSF: (ixx=63.7248239325, iyy=63.7248239325, ixy=-3.79858632292e-16), (2.0634e-16, 2.0936e-17)) [ 0.09142004] Using model DoubleGaussian DIFFS: (-0.0001572490117598259, 0.0009619403876283553) PSF: (ixx=16.169975098, iyy=16.1699215778, ixy=-1.24287220881e-05), (7.8807e-07, 2.8255e-06)) [ 0.19159612] PSF: (ixx=67.2220132981, iyy=67.2225928636, ixy=0.000126914960634), (2.2892e-07, 4.0119e-07)) [ 0.09126995]
            Hide
            pgee Perry Gee added a comment -

            Note that nGauss2 finds a two Gaussian fit to a single gaussian which splits the flux between two gaussians of nearly equal sigma and flux.

            Show
            pgee Perry Gee added a comment - Note that nGauss2 finds a two Gaussian fit to a single gaussian which splits the flux between two gaussians of nearly equal sigma and flux.
            Hide
            jbosch Jim Bosch added a comment -

            Looks good. One question: did finding and fixing the Jacobian bug improve the speed of the algorithm at all? No need for lots of new tests; I was just curious whether the slow performance you saw before went away at all.

            Show
            jbosch Jim Bosch added a comment - Looks good. One question: did finding and fixing the Jacobian bug improve the speed of the algorithm at all? No need for lots of new tests; I was just curious whether the slow performance you saw before went away at all.
            Hide
            pgee Perry Gee added a comment -

            Yes, I was just sending you email about that. The EmPsfApprox algorithm seems fine now. Note comparison with ShapeletPsfApprox models of similar order.

            Show
            pgee Perry Gee added a comment - Yes, I was just sending you email about that. The EmPsfApprox algorithm seems fine now. Note comparison with ShapeletPsfApprox models of similar order.
            Hide
            pgee Perry Gee added a comment -

            I think that all the questions for 6124 and 6125 were answered by the timing information I sent you. Yes, I think the plugin is working well now, and is faster. It is about as good as the comparable lower order ShapeletPsfApprox models at reproducing the input Psf. And the CModel + EmPsfApprox pair seems to work comparably.

            Show
            pgee Perry Gee added a comment - I think that all the questions for 6124 and 6125 were answered by the timing information I sent you. Yes, I think the plugin is working well now, and is faster. It is about as good as the comparable lower order ShapeletPsfApprox models at reproducing the input Psf. And the CModel + EmPsfApprox pair seems to work comparably.

              People

              Assignee:
              pgee Perry Gee
              Reporter:
              pgee Perry Gee
              Reviewers:
              Jim Bosch
              Watchers:
              Jim Bosch, Perry Gee
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              0 Vote for this issue
              Watchers:
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                Created:
                Updated:
                Resolved:

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