コード例 #1
0
def test_twodstats():
    """Make sure we can execute and print a readout of the plot
    """
    if __name__ == '__main__':
        logger = piff.config.setup_logger(2)
    else:
        logger = None

    model = piff.Gaussian(fastfit=True)
    interp = piff.Polynomial(order=1)  # should find that order=1 is better
    # create background model
    stars, true_model = generate_starlist(100)
    psf = piff.SimplePSF(model, interp)
    psf.fit(stars, None, None)

    # check the coeffs of sigma and g2, which are actually linear fits
    # skip g1 since it is actually a 2d parabola
    # factor of 0.263 is to account for going from pixel xy to wcs uv
    np.testing.assert_almost_equal(psf.interp.coeffs[0].flatten(),
                                   np.array([0.4, 0, 1. / (0.263 * 2048), 0]), decimal=4)
    np.testing.assert_almost_equal(psf.interp.coeffs[2].flatten(),
                                   np.array([-0.1 * 1000 / 2048, 0, 0.1 / (0.263 * 2048), 0]),
                                   decimal=4)

    stats = piff.TwoDHistStats(number_bins_u=5, number_bins_v=5, reducing_function='np.mean')
    stats.compute(psf, stars, logger=logger)
    # check the twodhists
    # get the average value in the bin
    u_i = 3
    v_i = 3
    icen = stats.twodhists['u'][v_i, u_i] / 0.263
    jcen = stats.twodhists['v'][v_i, u_i] / 0.263
    print('icen = ',icen)
    print('jcen = ',jcen)
    icenter = 1000
    jcenter = 2000
    # the average value in the bin should match up with the model for the average coordinates
    sigma, g1, g2 = psf_model(icen, jcen, icenter, jcenter)
    sigma_average = stats.twodhists['T'][v_i, u_i]
    g1_average = stats.twodhists['g1'][v_i, u_i]
    g2_average = stats.twodhists['g2'][v_i, u_i]
    # assert equal to 4th decimal
    print('sigma, g1, g2 = ',[sigma,g1,g2])
    print('av sigma, g1, g2 = ',[sigma_average,g1_average,g2_average])
    np.testing.assert_almost_equal([sigma, g1, g2], [sigma_average, g1_average, g2_average],
                                   decimal=2)

    # Test the plotting and writing
    twodstats_file = os.path.join('output','twodstats.pdf')
    stats.write(twodstats_file)

    # repeat for whisker
    stats = piff.WhiskerStats(number_bins_u=21, number_bins_v=21, reducing_function='np.mean')
    stats.compute(psf, stars)
    # Test the plotting and writing
    twodstats_file = os.path.join('output','whiskerstats.pdf')
    stats.write(twodstats_file)
コード例 #2
0
def test_extra_interp():
    # Test that specifying extra_interp_properties works properly
    # TODO: This is a very bare bones test of the interface.  There is basically no test of
    #       this functionality at all yet.  TBD!

    sigma = 1.3
    g1 = 0.23
    g2 = -0.17
    psf = galsim.Gaussian(sigma=sigma).shear(g1=g1, g2=g2)
    wcs = galsim.JacobianWCS(0.26, 0.05, -0.08, -0.29)
    image = galsim.Image(64, 64, wcs=wcs)
    psf.drawImage(image, method='no_pixel')

    # use g-i color as an extra property for interpolation.
    props = dict(gi_color=0.3)
    print('props = ', props)
    star = piff.Star(piff.StarData(image, image.true_center, properties=props),
                     None)

    model = piff.Gaussian(fastfit=True, include_pixel=False)
    interp = piff.Mean()
    psf = piff.SimplePSF(model, interp, extra_interp_properties=['gi_color'])
    assert psf.extra_interp_properties == ['gi_color']

    # Note: Mean doesn't actually do anything useful with the extra properties, so this
    #       isn't really testing anything other than that the code doesn't completely break.
    pointing = galsim.CelestialCoord(-5 * galsim.arcmin, -25 * galsim.degrees)
    psf.fit([star], wcs={0: wcs}, pointing=pointing)

    # Not much of a check here.  Just check that it actually draws something with flux ~= 1
    im = psf.draw(x=5, y=7, gi_color=0.3)
    np.testing.assert_allclose(im.array.sum(), 1.0, rtol=1.e-3)

    # Check missing or extra properties
    with np.testing.assert_raises(TypeError):
        psf.draw(x=5, y=7)
    with np.testing.assert_raises(TypeError):
        psf.draw(x=5, y=7, gi_color=0.3, ri_color=3)

    # No stars raises an error.  (This can happen in practice if all stars are excluded on input.)
    with np.testing.assert_raises(RuntimeError):
        psf.fit([], wcs={0: wcs}, pointing=pointing)

    # Also for SingleChipPSf
    psf2 = piff.SingleChipPSF(psf, extra_interp_properties=['gi_color'])
    assert psf2.extra_interp_properties == ['gi_color']

    with np.testing.assert_raises(TypeError):
        psf2.draw(x=5, y=7, chipnum=0)
コード例 #3
0
def test_load_images():
    """Test the load_images function
    """
    if __name__ == '__main__':
        logger = piff.config.setup_logger(verbose=2)
    else:
        logger = piff.config.setup_logger(
            log_file='output/test_load_image2.log')

    # Same setup as test_single_image, but without flags
    image = galsim.Image(2048, 2048, scale=0.26)
    x_list = [
        123.12, 345.98, 567.25, 1094.94, 924.15, 1532.74, 1743.11, 888.39,
        1033.29, 1409.31
    ]
    y_list = [
        345.43, 567.45, 1094.32, 924.29, 1532.92, 1743.83, 888.83, 1033.19,
        1409.20, 123.11
    ]
    sigma = 1.3
    g1 = 0.23
    g2 = -0.17
    psf = galsim.Gaussian(sigma=sigma).shear(g1=g1, g2=g2)
    for x, y in zip(x_list, y_list):
        bounds = galsim.BoundsI(int(x - 31), int(x + 32), int(y - 31),
                                int(y + 32))
        psf.drawImage(image[bounds],
                      center=galsim.PositionD(x, y),
                      method='no_pixel')
    image.addNoise(
        galsim.GaussianNoise(rng=galsim.BaseDeviate(1234), sigma=1e-6))
    image_file = os.path.join('output', 'test_load_images_im.fits')
    image.write(image_file)

    dtype = [('x', 'f8'), ('y', 'f8')]
    data = np.empty(len(x_list), dtype=dtype)
    data['x'] = x_list
    data['y'] = y_list
    cat_file = os.path.join('output', 'test_load_images_cat.fits')
    fitsio.write(cat_file, data, clobber=True)

    # Make star data
    config = {'image_file_name': image_file, 'cat_file_name': cat_file}
    orig_stars, wcs, pointing = piff.Input.process(config, logger)

    # Fit these with a simple Mean, Gaussian
    model = piff.Gaussian()
    interp = piff.Mean()
    psf = piff.SimplePSF(model, interp)
    psf.fit(orig_stars, wcs, pointing, logger=logger)
    psf_file = os.path.join('output', 'test_load_images_psf.fits')
    psf.write(psf_file, logger)

    # Read this file back in.  It has the star data, but the images are blank.
    psf2 = piff.read(psf_file, logger)
    assert len(psf2.stars) == 10
    for star in psf2.stars:
        np.testing.assert_array_equal(star.image.array, 0.)

    loaded_stars = piff.Star.load_images(psf2.stars, image_file)
    for star, orig in zip(loaded_stars, psf.stars):
        np.testing.assert_array_equal(star.image.array, orig.image.array)

    # Can optionally supply sky to subtract
    loaded_stars = piff.Star.load_images(psf2.stars, image_file, sky=10)
    for star, orig in zip(loaded_stars, psf.stars):
        np.testing.assert_array_equal(star.image.array, orig.image.array - 10)
コード例 #4
0
def test_single_image():
    """Test the simple case of one image and one catalog.
    """
    if __name__ == '__main__':
        logger = piff.config.setup_logger(verbose=2)
    else:
        logger = piff.config.setup_logger(
            log_file='output/test_single_image.log')

    # Make the image
    image = galsim.Image(2048, 2048, scale=0.26)

    # Where to put the stars.  Include some flagged and not used locations.
    x_list = [
        123.12, 345.98, 567.25, 1094.94, 924.15, 1532.74, 1743.11, 888.39,
        1033.29, 1409.31
    ]
    y_list = [
        345.43, 567.45, 1094.32, 924.29, 1532.92, 1743.83, 888.83, 1033.19,
        1409.20, 123.11
    ]
    flag_list = [1, 1, 13, 1, 1, 4, 1, 1, 0, 1]

    # Draw a Gaussian PSF at each location on the image.
    sigma = 1.3
    g1 = 0.23
    g2 = -0.17
    psf = galsim.Gaussian(sigma=sigma).shear(g1=g1, g2=g2)
    for x, y, flag in zip(x_list, y_list, flag_list):
        bounds = galsim.BoundsI(int(x - 31), int(x + 32), int(y - 31),
                                int(y + 32))
        offset = galsim.PositionD(x - int(x) - 0.5, y - int(y) - 0.5)
        psf.drawImage(image=image[bounds], method='no_pixel', offset=offset)
        # corrupt the ones that are marked as flagged
        if flag & 4:
            print('corrupting star at ', x, y)
            ar = image[bounds].array
            im_max = np.max(ar) * 0.2
            ar[ar > im_max] = im_max
    image.addNoise(
        galsim.GaussianNoise(rng=galsim.BaseDeviate(1234), sigma=1e-6))

    # Write out the image to a file
    image_file = os.path.join('output', 'simple_image.fits')
    image.write(image_file)

    # Write out the catalog to a file
    dtype = [('x', 'f8'), ('y', 'f8'), ('flag', 'i2')]
    data = np.empty(len(x_list), dtype=dtype)
    data['x'] = x_list
    data['y'] = y_list
    data['flag'] = flag_list
    cat_file = os.path.join('output', 'simple_cat.fits')
    fitsio.write(cat_file, data, clobber=True)

    # Use InputFiles to read these back in
    config = {'image_file_name': image_file, 'cat_file_name': cat_file}
    input = piff.InputFiles(config, logger=logger)
    assert input.image_file_name == [image_file]
    assert input.cat_file_name == [cat_file]

    # Check image
    assert input.nimages == 1
    image1, _, image_pos, _, _, _ = input.getRawImageData(0)
    np.testing.assert_equal(image1.array, image.array)

    # Check catalog
    np.testing.assert_equal([pos.x for pos in image_pos], x_list)
    np.testing.assert_equal([pos.y for pos in image_pos], y_list)

    # Repeat, using flag columns this time.
    config = {
        'image_file_name': image_file,
        'cat_file_name': cat_file,
        'flag_col': 'flag',
        'use_flag': '1',
        'skip_flag': '4',
        'stamp_size': 48
    }
    input = piff.InputFiles(config, logger=logger)
    assert input.nimages == 1
    _, _, image_pos, _, _, _ = input.getRawImageData(0)
    assert len(image_pos) == 7

    # Make star data
    orig_stars = input.makeStars()
    assert len(orig_stars) == 7
    assert orig_stars[0].image.array.shape == (48, 48)

    # Process the star data
    # can only compare to truth if include_pixel=False
    model = piff.Gaussian(fastfit=True, include_pixel=False)
    interp = piff.Mean()
    fitted_stars = [model.fit(model.initialize(star)) for star in orig_stars]
    interp.solve(fitted_stars)
    print('mean = ', interp.mean)

    # Check that the interpolation is what it should be
    # Any position would work here.
    chipnum = 0
    x = 1024
    y = 123
    orig_wcs = input.getWCS()[chipnum]
    orig_pointing = input.getPointing()
    image_pos = galsim.PositionD(x, y)
    world_pos = piff.StarData.calculateFieldPos(image_pos, orig_wcs,
                                                orig_pointing)
    u, v = world_pos.x, world_pos.y
    stamp_size = config['stamp_size']

    target = piff.Star.makeTarget(x=x,
                                  y=y,
                                  u=u,
                                  v=v,
                                  wcs=orig_wcs,
                                  stamp_size=stamp_size,
                                  pointing=orig_pointing)
    true_params = [sigma, g1, g2]
    test_star = interp.interpolate(target)
    np.testing.assert_almost_equal(test_star.fit.params,
                                   true_params,
                                   decimal=4)

    # Check default values of options
    psf = piff.SimplePSF(model, interp)
    assert psf.chisq_thresh == 0.1
    assert psf.max_iter == 30
    assert psf.outliers == None
    assert psf.extra_interp_properties == []

    # Now test running it via the config parser
    psf_file = os.path.join('output', 'simple_psf.fits')
    config = {
        'input': {
            'image_file_name': image_file,
            'cat_file_name': cat_file,
            'flag_col': 'flag',
            'use_flag': 1,
            'skip_flag': 4,
            'stamp_size': stamp_size
        },
        'psf': {
            'model': {
                'type': 'Gaussian',
                'fastfit': True,
                'include_pixel': False
            },
            'interp': {
                'type': 'Mean'
            },
            'max_iter': 10,
            'chisq_thresh': 0.2,
        },
        'output': {
            'file_name': psf_file
        },
    }
    orig_stars, wcs, pointing = piff.Input.process(config['input'], logger)

    # Use a SimplePSF to process the stars data this time.
    interp = piff.Mean()
    psf = piff.SimplePSF(model, interp, max_iter=10, chisq_thresh=0.2)
    assert psf.chisq_thresh == 0.2
    assert psf.max_iter == 10

    psf.fit(orig_stars, wcs, pointing, logger=logger)
    test_star = psf.interp.interpolate(target)
    np.testing.assert_almost_equal(test_star.fit.params,
                                   true_params,
                                   decimal=4)

    # test that drawStar and drawStarList work
    test_star = psf.drawStar(target)
    test_star_list = psf.drawStarList([target])[0]
    np.testing.assert_equal(test_star.fit.params, test_star_list.fit.params)
    np.testing.assert_equal(test_star.image.array, test_star_list.image.array)

    # test copy_image property of drawStar and draw
    for draw in [psf.drawStar, psf.model.draw]:
        target_star_copy = psf.interp.interpolate(
            piff.Star(target.data.copy(), target.fit.copy()))
        # interp is so that when we do psf.model.draw we have fit.params to work with

        test_star_copy = draw(target_star_copy, copy_image=True)
        test_star_nocopy = draw(target_star_copy, copy_image=False)
        # if we modify target_star_copy, then test_star_nocopy should be modified,
        # but not test_star_copy
        target_star_copy.image.array[0, 0] = 23456
        assert test_star_nocopy.image.array[
            0, 0] == target_star_copy.image.array[0, 0]
        assert test_star_copy.image.array[0,
                                          0] != target_star_copy.image.array[0,
                                                                             0]
        # however the other pixels SHOULD still be all the same value
        assert test_star_nocopy.image.array[
            1, 1] == target_star_copy.image.array[1, 1]
        assert test_star_copy.image.array[1,
                                          1] == target_star_copy.image.array[1,
                                                                             1]

    # test that draw works
    test_image = psf.draw(x=target['x'],
                          y=target['y'],
                          stamp_size=config['input']['stamp_size'],
                          flux=target.fit.flux,
                          offset=target.fit.center)
    # this image should be the same values as test_star
    assert test_image == test_star.image
    # test that draw does not copy the image
    image_ref = psf.draw(x=target['x'],
                         y=target['y'],
                         stamp_size=config['input']['stamp_size'],
                         flux=target.fit.flux,
                         offset=target.fit.center,
                         image=test_image)
    image_ref.array[0, 0] = 123456789
    assert test_image.array[0, 0] == image_ref.array[0, 0]
    assert test_star.image.array[0, 0] != test_image.array[0, 0]
    assert test_star.image.array[1, 1] == test_image.array[1, 1]

    # Round trip to a file
    psf.write(psf_file, logger)
    psf2 = piff.read(psf_file, logger)
    assert type(psf2.model) is piff.Gaussian
    assert type(psf2.interp) is piff.Mean
    assert psf2.chisq == psf.chisq
    assert psf2.last_delta_chisq == psf.last_delta_chisq
    assert psf2.chisq_thresh == psf.chisq_thresh
    assert psf2.max_iter == psf.max_iter
    assert psf2.dof == psf.dof
    assert psf2.nremoved == psf.nremoved
    test_star = psf2.interp.interpolate(target)
    np.testing.assert_almost_equal(test_star.fit.params,
                                   true_params,
                                   decimal=4)

    # Do the whole thing with the config parser
    os.remove(psf_file)

    piff.piffify(config, logger)
    psf3 = piff.read(psf_file)
    assert type(psf3.model) is piff.Gaussian
    assert type(psf3.interp) is piff.Mean
    assert psf3.chisq == psf.chisq
    assert psf3.last_delta_chisq == psf.last_delta_chisq
    assert psf3.chisq_thresh == psf.chisq_thresh
    assert psf3.max_iter == psf.max_iter
    assert psf3.dof == psf.dof
    assert psf3.nremoved == psf.nremoved
    test_star = psf3.interp.interpolate(target)
    np.testing.assert_almost_equal(test_star.fit.params,
                                   true_params,
                                   decimal=4)

    # Test using the piffify executable
    os.remove(psf_file)
    # This would be simpler as a direct assignment, but this once, test the way you would set
    # this from the command line, which would call parse_variables.
    piff.config.parse_variables(config, ['verbose=0'], logger=logger)
    #config['verbose'] = 0
    with open('simple.yaml', 'w') as f:
        f.write(yaml.dump(config, default_flow_style=False))
    config2 = piff.config.read_config('simple.yaml')
    assert config == config2
    piffify_exe = get_script_name('piffify')
    p = subprocess.Popen([piffify_exe, 'simple.yaml'])
    p.communicate()
    psf4 = piff.read(psf_file)
    assert type(psf4.model) is piff.Gaussian
    assert type(psf4.interp) is piff.Mean
    assert psf4.chisq == psf.chisq
    assert psf4.last_delta_chisq == psf.last_delta_chisq
    assert psf4.chisq_thresh == psf.chisq_thresh
    assert psf4.max_iter == psf.max_iter
    assert psf4.dof == psf.dof
    assert psf4.nremoved == psf.nremoved
    test_star = psf4.interp.interpolate(target)
    np.testing.assert_almost_equal(test_star.fit.params,
                                   true_params,
                                   decimal=4)

    # With very low max_iter, we hit the warning about non-convergence
    config['psf']['max_iter'] = 1
    with CaptureLog(level=1) as cl:
        piff.piffify(config, cl.logger)
    assert 'PSF fit did not converge' in cl.output
コード例 #5
0
def test_twodstats():
    """Make sure we can execute and print a readout of the plot
    """
    if __name__ == '__main__':
        logger = piff.config.setup_logger(2)
    else:
        logger = None

    model = piff.Gaussian(fastfit=True)
    interp = piff.Polynomial(order=1)  # should find that order=1 is better
    # create background model
    stars, true_model = generate_starlist(100)
    psf = piff.SimplePSF(model, interp)
    psf.fit(stars, None, None)
    stars = psf.stars  # These have the right fit parameters

    # check the coeffs of sigma and g2, which are actually linear fits
    # skip g1 since it is actually a 2d parabola
    # factor of 0.263 is to account for going from pixel xy to wcs uv
    np.testing.assert_almost_equal(psf.interp.coeffs[0].flatten(),
                                   np.array([0.4, 0, 1. / (0.263 * 2048), 0]),
                                   decimal=4)
    np.testing.assert_almost_equal(
        psf.interp.coeffs[2].flatten(),
        np.array([-0.1 * 1000 / 2048, 0, 0.1 / (0.263 * 2048), 0]),
        decimal=4)

    stats = piff.TwoDHistStats(nbins_u=5, nbins_v=5)  # implicitly np.median
    stats.compute(psf, stars, logger=logger)
    # check the twodhists
    # get the average value in the bin
    u_i = 3
    v_i = 3
    icen = stats.twodhists['u'][v_i, u_i] / 0.263
    jcen = stats.twodhists['v'][v_i, u_i] / 0.263
    print('icen = ', icen)
    print('jcen = ', jcen)
    icenter = 1000
    jcenter = 2000
    # the average value in the bin should match up with the model for the average coordinates
    sigma, g1, g2 = psf_model(icen, jcen, icenter, jcenter)
    sigma_average = stats.twodhists['T'][v_i, u_i]
    g1_average = stats.twodhists['g1'][v_i, u_i]
    g2_average = stats.twodhists['g2'][v_i, u_i]
    # assert equal to 4th decimal
    print('sigma, g1, g2 = ', [sigma, g1, g2])
    print('av sigma, g1, g2 = ', [sigma_average, g1_average, g2_average])
    np.testing.assert_almost_equal([sigma, g1, g2],
                                   [sigma_average, g1_average, g2_average],
                                   decimal=2)

    # Test the plotting and writing
    twodstats_file = os.path.join('output', 'twodstats.pdf')
    stats.write(twodstats_file)

    with np.testing.assert_raises(ValueError):
        stats.write()  # If not given in constructor, must give file name here.

    # repeat for whisker
    stats = piff.WhiskerStats(nbins_u=21,
                              nbins_v=21,
                              reducing_function='np.mean')
    stats.compute(psf, stars)
    # Test the plotting and writing
    whisker_file = os.path.join('output', 'whiskerstats.pdf')
    stats.write(whisker_file)
    with np.testing.assert_raises(ValueError):
        stats.write()

    # With large number of bins, many will have no objects.  This is ok.
    # Also, can use other np functions like max, std, instead to get different stats
    # Not sure when these would be useful, but they are allowed.
    # And, check usage where file_name is given in init.
    twodstats_file2 = os.path.join('output', 'twodstats.pdf')
    stats2 = piff.TwoDHistStats(nbins_u=50,
                                nbins_v=50,
                                reducing_function='np.std',
                                file_name=twodstats_file2)
    with np.testing.assert_raises(RuntimeError):
        stats2.write()  # Cannot write before compute
    stats2.compute(psf, stars, logger=logger)
    stats2.write()

    whisker_file2 = os.path.join('output', 'whiskerstats.pdf')
    stats2 = piff.WhiskerStats(nbins_u=100,
                               nbins_v=100,
                               reducing_function='np.max',
                               file_name=whisker_file2)
    with np.testing.assert_raises(RuntimeError):
        stats2.write()  # Cannot write before compute
    stats2.compute(psf, stars)
    stats2.write()
コード例 #6
0
ファイル: test_pixel.py プロジェクト: sarahburnett/Piff
def test_des_image():
    """Test the whole process with a DES CCD.
    """
    import os
    import fitsio

    image_file = 'y1_test/DECam_00241238_01.fits.fz'
    cat_file = 'y1_test/DECam_00241238_01_psfcat_tb_maxmag_17.0_magcut_3.0_findstars.fits'
    orig_image = galsim.fits.read(image_file)
    psf_file = os.path.join('output', 'pixel_des_psf.fits')

    if __name__ == '__main__':
        # These match what Gary used in fit_des.py
        nstars = None
        scale = 0.15
        size = 41
    else:
        # These are faster and good enough for the unit tests.
        nstars = 25
        scale = 0.2
        size = 21
    stamp_size = 51

    # The configuration dict with the right input fields for the file we're using.
    start_sigma = 1.0 / 2.355  # TODO: Need to make this automatic somehow.
    config = {
        'input': {
            'images': image_file,
            'image_hdu': 1,
            'weight_hdu': 3,
            'badpix_hdu': 2,
            'cats': cat_file,
            'cat_hdu': 2,
            'x_col': 'XWIN_IMAGE',
            'y_col': 'YWIN_IMAGE',
            'sky_col': 'BACKGROUND',
            'stamp_size': stamp_size,
            'ra': 'TELRA',
            'dec': 'TELDEC',
            'gain': 'GAINA',
        },
        'output': {
            'file_name': psf_file,
        },
        'psf': {
            'model': {
                'type': 'PixelGrid',
                'scale': scale,
                'size': size,
                'start_sigma': start_sigma,
            },
            'interp': {
                'type': 'BasisPolynomial',
                'order': 2,
            },
        },
    }
    if __name__ == '__main__': config['verbose'] = 3

    # These tests are slow, and it's really just doing the same thing three times, so
    # only do the first one when running via nosetests.
    if True:
        # Start by doing things manually:
        if __name__ == '__main__':
            logger = piff.config.setup_logger(2)
        else:
            logger = None

        # Largely copied from Gary's fit_des.py, but using the Piff input_handler to
        # read the input files.
        stars, wcs, pointing = piff.Input.process(config['input'],
                                                  logger=logger)
        if nstars is not None:
            stars = stars[:nstars]

        # Make model, force PSF centering
        model = piff.PixelGrid(scale=scale,
                               size=size,
                               interp=piff.Lanczos(3),
                               force_model_center=True,
                               start_sigma=start_sigma,
                               logger=logger)

        # Interpolator will be zero-order polynomial.
        # Find u, v ranges
        interp = piff.BasisPolynomial(order=2, logger=logger)

        # Make a psf
        psf = piff.SimplePSF(model, interp)
        psf.fit(stars, wcs, pointing, logger=logger)

        # The difference between the images of the fitted stars and the originals should be
        # consistent with noise.  Keep track of how many don't meet that goal.
        n_bad = 0  # chisq/dof > 2
        n_marginal = 0  # chisq/dof > 1.1
        n_good = 0  # chisq/dof <= 1.1
        # Note: The 2 and 1.1 values here are very arbitrary!

        for s in psf.stars:
            fitted = psf.drawStar(s)
            orig_stamp = orig_image[fitted.image.bounds] - s['sky']
            fit_stamp = fitted.image

            x0 = int(s['x'] + 0.5)
            y0 = int(s['y'] + 0.5)
            b = galsim.BoundsI(x0 - 3, x0 + 3, y0 - 3, y0 + 3)
            #print('orig center = ',orig_stamp[b].array)
            #print('flux = ',orig_stamp.array.sum())
            #print('fit center = ',fit_stamp[b].array)
            #print('flux = ',fit_stamp.array.sum())
            flux = fitted.fit.flux
            #print('max diff/flux = ',np.max(np.abs(orig_stamp.array-fit_stamp.array))/flux)
            #np.testing.assert_almost_equal(fit_stamp.array/flux, orig_stamp.array/flux, decimal=2)
            weight = s.weight  # These should be 1/var_pix
            resid = fit_stamp - orig_stamp
            chisq = np.sum(resid.array**2 * weight.array)
            print('chisq = ', chisq)
            print('cf. star.chisq, dof = ', s.fit.chisq, s.fit.dof)
            assert abs(chisq - s.fit.chisq) < 1.e-3 * chisq
            if chisq > 2. * s.fit.dof:
                n_bad += 1
            elif chisq > 1.1 * s.fit.dof:
                n_marginal += 1
            else:
                n_good += 1

            # Check the convenience function that an end user would typically use
            offset = s.center_to_offset(s.fit.center)
            image = psf.draw(x=s['x'],
                             y=s['y'],
                             stamp_size=stamp_size,
                             flux=s.fit.flux,
                             offset=offset)
            np.testing.assert_almost_equal(image.array,
                                           fit_stamp.array,
                                           decimal=4)

        print('n_good, marginal, bad = ', n_good, n_marginal, n_bad)
        # The real counts are 10 and 2.  So this says make sure any updates to the code don't make
        # things much worse.
        assert n_marginal <= 12
        assert n_bad <= 3

    # Use piffify function
    if __name__ == '__main__':
        print('start piffify')
        piff.piffify(config)
        print('read stars')
        stars, wcs, pointing = piff.Input.process(config['input'])
        print('read psf')
        psf = piff.read(psf_file)
        stars = [psf.model.initialize(s) for s in stars]
        flux = stars[0].fit.flux
        offset = stars[0].center_to_offset(stars[0].fit.center)
        fit_stamp = psf.draw(x=stars[0]['x'],
                             y=stars[0]['y'],
                             stamp_size=stamp_size,
                             flux=flux,
                             offset=offset)
        orig_stamp = orig_image[stars[0].image.bounds] - stars[0]['sky']
        # The first star happens to be a good one, so go ahead and test the arrays directly.
        np.testing.assert_almost_equal(fit_stamp.array / flux,
                                       orig_stamp.array / flux,
                                       decimal=2)

    # Test using the piffify executable
    config['verbose'] = 0
    with open('pixel_des.yaml', 'w') as f:
        f.write(yaml.dump(config, default_flow_style=False))
    if __name__ == '__main__':
        if os.path.exists(psf_file):
            os.remove(psf_file)
        piffify_exe = get_script_name('piffify')
        print('start piffify executable')
        p = subprocess.Popen([piffify_exe, 'pixel_des.yaml'])
        p.communicate()
        print('read stars')
        stars, wcs, pointing = piff.Input.process(config['input'])
        print('read psf')
        psf = piff.read(psf_file)
        stars = [psf.model.initialize(s) for s in stars]
        flux = stars[0].fit.flux
        offset = stars[0].center_to_offset(stars[0].fit.center)
        fit_stamp = psf.draw(x=stars[0]['x'],
                             y=stars[0]['y'],
                             stamp_size=stamp_size,
                             flux=flux,
                             offset=offset)
        orig_stamp = orig_image[stars[0].image.bounds] - stars[0]['sky']
        np.testing.assert_almost_equal(fit_stamp.array / flux,
                                       orig_stamp.array / flux,
                                       decimal=2)
コード例 #7
0
ファイル: test_pixel.py プロジェクト: sarahburnett/Piff
def test_single_image():
    """Test the whole process with a single image.

    Note: This test is based heavily on test_single_image in test_simple.py.
    """
    import os
    import fitsio
    np_rng = np.random.RandomState(1234)

    # Make the image
    image = galsim.Image(2048, 2048, scale=0.2)

    # The (x,y) values will be on a grid 5 x 5 stars with a random sub-pixel offset.
    xvals = np.linspace(50., 1950., 5)
    yvals = np.linspace(50., 1950., 5)
    x_list, y_list = np.meshgrid(xvals, yvals)
    x_list = x_list.flatten()
    y_list = y_list.flatten()
    x_list = x_list + (np_rng.rand(len(x_list)) - 0.5)
    y_list = y_list + (np_rng.rand(len(x_list)) - 0.5)
    print('x_list = ', x_list)
    print('y_list = ', y_list)
    # Range of fluxes from 100 to 15000
    flux_list = 100. * np.exp(5. * np_rng.rand(len(x_list)))
    print('fluxes range from ', np.min(flux_list), np.max(flux_list))

    # Draw a Moffat PSF at each location on the image.
    # Have the truth values vary quadratically across the image.
    beta_fn = lambda x, y: 3.5 - 0.1 * (x / 1000) + 0.08 * (y / 1000)**2
    fwhm_fn = lambda x, y: 0.9 + 0.05 * (x / 1000) - 0.03 * (
        y / 1000) + 0.02 * (x / 1000) * (y / 1000)
    e1_fn = lambda x, y: 0.02 - 0.01 * (x / 1000)
    e2_fn = lambda x, y: -0.03 + 0.02 * (x / 1000)**2 - 0.01 * (y / 1000) * 2

    for x, y, flux in zip(x_list, y_list, flux_list):
        beta = beta_fn(x, y)
        fwhm = fwhm_fn(x, y)
        e1 = e1_fn(x, y)
        e2 = e2_fn(x, y)
        print(x, y, beta, fwhm, e1, e2)
        moffat = galsim.Moffat(fwhm=fwhm, beta=beta, flux=flux).shear(e1=e1,
                                                                      e2=e2)
        bounds = galsim.BoundsI(int(x - 31), int(x + 32), int(y - 31),
                                int(y + 32))
        offset = galsim.PositionD(x - int(x) - 0.5, y - int(y) - 0.5)
        moffat.drawImage(image=image[bounds], offset=offset, method='no_pixel')
    print('drew image')

    # Write out the image to a file
    image_file = os.path.join('data', 'pixel_moffat_image.fits')
    image.write(image_file)
    print('wrote image')

    # Write out the catalog to a file
    dtype = [('x', 'f8'), ('y', 'f8')]
    data = np.empty(len(x_list), dtype=dtype)
    data['x'] = x_list
    data['y'] = y_list
    cat_file = os.path.join('data', 'pixel_moffat_cat.fits')
    fitsio.write(cat_file, data, clobber=True)
    print('wrote catalog')

    # Use InputFiles to read these back in
    input = piff.InputFiles(image_file, cat_file, stamp_size=32)
    assert input.image_files == [image_file]
    assert input.cat_files == [cat_file]
    assert input.x_col == 'x'
    assert input.y_col == 'y'

    # Check image
    input.readImages()
    assert len(input.images) == 1
    np.testing.assert_equal(input.images[0].array, image.array)

    # Check catalog
    input.readStarCatalogs()
    assert len(input.cats) == 1
    np.testing.assert_equal(input.cats[0]['x'], x_list)
    np.testing.assert_equal(input.cats[0]['y'], y_list)

    # Make stars
    orig_stars = input.makeStars()
    assert len(orig_stars) == len(x_list)
    assert orig_stars[0].image.array.shape == (32, 32)

    # Make a test star, not at the location of any of the model stars to use for each of the
    # below tests.
    x0 = 1024  # Some random position, not where a star was originally.
    y0 = 133
    beta = beta_fn(x0, y0)
    fwhm = fwhm_fn(x0, y0)
    e1 = e1_fn(x0, y0)
    e2 = e2_fn(x0, y0)
    moffat = galsim.Moffat(fwhm=fwhm, beta=beta).shear(e1=e1, e2=e2)
    target_star = piff.Star.makeTarget(x=x0, y=y0, scale=image.scale)
    test_im = galsim.ImageD(bounds=target_star.image.bounds, scale=image.scale)
    moffat.drawImage(image=test_im, method='no_pixel', use_true_center=False)
    print('made test star')

    # These tests are slow, and it's really just doing the same thing three times, so
    # only do the first one when running via nosetests.
    if True:
        # Process the star data
        model = piff.PixelGrid(0.2, 16, start_sigma=0.9 / 2.355)
        interp = piff.BasisPolynomial(order=2)
        if __name__ == '__main__':
            logger = piff.config.setup_logger(2)
        else:
            logger = None
        pointing = None  # wcs is not Celestial here, so pointing needs to be None.
        psf = piff.SimplePSF(model, interp)
        psf.fit(orig_stars, {0: input.images[0].wcs}, pointing, logger=logger)

        # Check that the interpolation is what it should be
        print('target.flux = ', target_star.fit.flux)
        test_star = psf.drawStar(target_star)
        #print('test_im center = ',test_im[b].array)
        #print('flux = ',test_im.array.sum())
        #print('interp_im center = ',test_star.image[b].array)
        #print('flux = ',test_star.image.array.sum())
        #print('max diff = ',np.max(np.abs(test_star.image.array-test_im.array)))
        np.testing.assert_almost_equal(test_star.image.array,
                                       test_im.array,
                                       decimal=3)

        # Check the convenience function that an end user would typically use
        image = psf.draw(x=x0, y=y0)
        np.testing.assert_almost_equal(image.array, test_im.array, decimal=3)

        # Round trip through a file
        psf_file = os.path.join('output', 'pixel_psf.fits')
        psf.write(psf_file, logger)
        psf = piff.read(psf_file, logger)
        assert type(psf.model) is piff.PixelGrid
        assert type(psf.interp) is piff.BasisPolynomial
        test_star = psf.drawStar(target_star)
        np.testing.assert_almost_equal(test_star.image.array,
                                       test_im.array,
                                       decimal=3)

        # Check the convenience function that an end user would typically use
        image = psf.draw(x=x0, y=y0)
        np.testing.assert_almost_equal(image.array, test_im.array, decimal=3)

    # Do the whole thing with the config parser
    config = {
        'input': {
            'images': image_file,
            'cats': cat_file,
            'x_col': 'x',
            'y_col': 'y',
            'stamp_size': 48  # Bigger than we drew, but should still work.
        },
        'output': {
            'file_name': psf_file
        },
        'psf': {
            'model': {
                'type': 'PixelGrid',
                'scale': 0.2,
                'size':
                16,  # Much smaller than the input stamps, but this is plenty here.
                'start_sigma': 0.9 / 2.355
            },
            'interp': {
                'type': 'BasisPolynomial',
                'order': 2
            },
        },
    }
    if __name__ == '__main__':
        print("Running piffify function")
        piff.piffify(config)
        psf = piff.read(psf_file)
        test_star = psf.drawStar(target_star)
        np.testing.assert_almost_equal(test_star.image.array,
                                       test_im.array,
                                       decimal=3)

    # Test using the piffify executable
    config['verbose'] = 0
    with open('pixel_moffat.yaml', 'w') as f:
        f.write(yaml.dump(config, default_flow_style=False))
    if __name__ == '__main__':
        print("Running piffify executable")
        if os.path.exists(psf_file):
            os.remove(psf_file)
        piffify_exe = get_script_name('piffify')
        p = subprocess.Popen([piffify_exe, 'pixel_moffat.yaml'])
        p.communicate()
        psf = piff.read(psf_file)
        test_star = psf.drawStar(target_star)
        np.testing.assert_almost_equal(test_star.image.array,
                                       test_im.array,
                                       decimal=3)
コード例 #8
0
ファイル: test_simple.py プロジェクト: sarahburnett/Piff
def test_single_image():
    """Test the simple case of one image and one catalog.
    """
    # Make the image
    image = galsim.Image(2048, 2048, scale=0.26)

    # Where to put the stars.  Include some flagged and not used locations.
    x_list = [
        123.12, 345.98, 567.25, 1094.94, 924.15, 1532.74, 1743.11, 888.39,
        1033.29, 1409.31
    ]
    y_list = [
        345.43, 567.45, 1094.32, 924.29, 1532.92, 1743.83, 888.83, 1033.19,
        1409.20, 123.11
    ]
    flag_list = [0, 0, 12, 0, 0, 1, 0, 0, 0, 0]
    use_list = [1, 1, 1, 1, 1, 0, 1, 1, 0, 1]

    # Draw a Gaussian PSF at each location on the image.
    sigma = 1.3
    g1 = 0.23
    g2 = -0.17
    psf = galsim.Gaussian(sigma=sigma).shear(g1=g1, g2=g2)
    for x, y, flag, use in zip(x_list, y_list, flag_list, use_list):
        bounds = galsim.BoundsI(int(x - 31), int(x + 32), int(y - 31),
                                int(y + 32))
        offset = galsim.PositionD(x - int(x) - 0.5, y - int(y) - 0.5)
        psf.drawImage(image=image[bounds], method='no_pixel', offset=offset)
        # corrupt the ones that are marked as flagged
        if flag:
            print('corrupting star at ', x, y)
            ar = image[bounds].array
            im_max = np.max(ar) * 0.2
            ar[ar > im_max] = im_max
    image.addNoise(
        galsim.GaussianNoise(rng=galsim.BaseDeviate(1234), sigma=1e-6))

    # Write out the image to a file
    image_file = os.path.join('data', 'simple_image.fits')
    image.write(image_file)

    # Write out the catalog to a file
    dtype = [('x', 'f8'), ('y', 'f8'), ('flag', 'i2'), ('use', 'i2')]
    data = np.empty(len(x_list), dtype=dtype)
    data['x'] = x_list
    data['y'] = y_list
    data['flag'] = flag_list
    data['use'] = use_list
    cat_file = os.path.join('data', 'simple_cat.fits')
    fitsio.write(cat_file, data, clobber=True)

    # Use InputFiles to read these back in
    input = piff.InputFiles(image_file, cat_file)
    assert input.image_files == [image_file]
    assert input.cat_files == [cat_file]
    assert input.x_col == 'x'
    assert input.y_col == 'y'

    # Check image
    input.readImages()
    assert len(input.images) == 1
    np.testing.assert_equal(input.images[0].array, image.array)

    # Check catalog
    input.readStarCatalogs()
    assert len(input.cats) == 1
    np.testing.assert_equal(input.cats[0]['x'], x_list)
    np.testing.assert_equal(input.cats[0]['y'], y_list)

    # Repeat, using flag and use columns this time.
    input = piff.InputFiles(image_file,
                            cat_file,
                            flag_col='flag',
                            use_col='use',
                            stamp_size=48)
    assert input.flag_col == 'flag'
    assert input.use_col == 'use'
    input.readImages()
    input.readStarCatalogs()
    assert len(input.cats[0]) == 7

    # Make star data
    orig_stars = input.makeStars()
    assert len(orig_stars) == 7
    assert orig_stars[0].image.array.shape == (48, 48)

    # Process the star data
    # can only compare to truth if include_pixel=False
    model = piff.Gaussian(fastfit=True, include_pixel=False)
    interp = piff.Mean()
    fitted_stars = [model.fit(model.initialize(star)) for star in orig_stars]
    interp.solve(fitted_stars)
    print('mean = ', interp.mean)

    # Check that the interpolation is what it should be
    target = piff.Star.makeTarget(x=1024,
                                  y=123)  # Any position would work here.
    true_params = [sigma, g1, g2]
    test_star = interp.interpolate(target)
    np.testing.assert_almost_equal(test_star.fit.params,
                                   true_params,
                                   decimal=4)

    # Now test running it via the config parser
    psf_file = os.path.join('output', 'simple_psf.fits')
    config = {
        'input': {
            'images': image_file,
            'cats': cat_file,
            'flag_col': 'flag',
            'use_col': 'use',
            'stamp_size': 48
        },
        'psf': {
            'model': {
                'type': 'Gaussian',
                'fastfit': True,
                'include_pixel': False
            },
            'interp': {
                'type': 'Mean'
            },
        },
        'output': {
            'file_name': psf_file
        },
    }
    if __name__ == '__main__':
        logger = piff.config.setup_logger(verbose=2)
    else:
        logger = piff.config.setup_logger(verbose=0)
    orig_stars, wcs, pointing = piff.Input.process(config['input'], logger)

    # Use a SimplePSF to process the stars data this time.
    psf = piff.SimplePSF(model, interp)

    psf.fit(orig_stars, wcs, pointing, logger=logger)
    test_star = psf.interp.interpolate(target)
    np.testing.assert_almost_equal(test_star.fit.params,
                                   true_params,
                                   decimal=4)

    # Round trip to a file
    psf.write(psf_file, logger)
    psf = piff.read(psf_file, logger)
    assert type(psf.model) is piff.Gaussian
    assert type(psf.interp) is piff.Mean
    test_star = psf.interp.interpolate(target)
    np.testing.assert_almost_equal(test_star.fit.params,
                                   true_params,
                                   decimal=4)

    # Do the whole thing with the config parser
    os.remove(psf_file)

    piff.piffify(config, logger)
    psf = piff.read(psf_file)
    test_star = psf.interp.interpolate(target)
    np.testing.assert_almost_equal(test_star.fit.params,
                                   true_params,
                                   decimal=4)

    # Test using the piffify executable
    os.remove(psf_file)
    config['verbose'] = 0
    with open('simple.yaml', 'w') as f:
        f.write(yaml.dump(config, default_flow_style=False))
    piffify_exe = get_script_name('piffify')
    p = subprocess.Popen([piffify_exe, 'simple.yaml'])
    p.communicate()
    psf = piff.read(psf_file)
    test_star = psf.interp.interpolate(target)
    np.testing.assert_almost_equal(test_star.fit.params,
                                   true_params,
                                   decimal=4)

    # Test that we can make rho statistics
    min_sep = 1
    max_sep = 100
    bin_size = 0.1
    stats = piff.RhoStats(min_sep=min_sep, max_sep=max_sep, bin_size=bin_size)
    stats.compute(psf, orig_stars)

    rhos = [stats.rho1, stats.rho2, stats.rho3, stats.rho4, stats.rho5]
    for rho in rhos:
        # Test the range of separations
        radius = np.exp(rho.logr)
        # last bin can be one bigger than max_sep
        np.testing.assert_array_less(radius,
                                     np.exp(np.log(max_sep) + bin_size))
        np.testing.assert_array_less(min_sep, radius)
        np.testing.assert_array_almost_equal(np.diff(rho.logr),
                                             bin_size,
                                             decimal=5)

        # Test that the max absolute value of each rho isn't crazy
        np.testing.assert_array_less(np.abs(rho.xip), 1)

        # # Check that each rho isn't precisely zero. This means the sum of abs > 0
        np.testing.assert_array_less(0, np.sum(np.abs(rho.xip)))

    # Test the plotting and writing
    rho_psf_file = os.path.join('output', 'simple_psf_rhostats.pdf')
    stats.write(rho_psf_file)

    # Test that we can make summary shape statistics, using HSM
    shapeStats = piff.ShapeHistogramsStats()
    shapeStats.compute(psf, orig_stars)

    # test their characteristics
    np.testing.assert_array_almost_equal(sigma, shapeStats.T, decimal=4)
    np.testing.assert_array_almost_equal(sigma, shapeStats.T_model, decimal=3)
    np.testing.assert_array_almost_equal(g1, shapeStats.g1, decimal=4)
    np.testing.assert_array_almost_equal(g1, shapeStats.g1_model, decimal=3)
    np.testing.assert_array_almost_equal(g2, shapeStats.g2, decimal=4)
    np.testing.assert_array_almost_equal(g2, shapeStats.g2_model, decimal=3)

    shape_psf_file = os.path.join('output', 'simple_psf_shapestats.pdf')
    shapeStats.write(shape_psf_file)

    # Test that we can use the config parser for both RhoStats and ShapeHistogramsStats
    config['output']['stats'] = [
        {
            'type': 'ShapeHistograms',
            'file_name': shape_psf_file
        },
        {
            'type': 'Rho',
            'file_name': rho_psf_file
        },
        {
            'type': 'TwoDHist',
            'file_name': os.path.join('output',
                                      'simple_psf_twodhiststats.pdf'),
            'number_bins_u': 3,
            'number_bins_v': 3,
        },
        {
            'type': 'TwoDHist',
            'file_name': os.path.join('output',
                                      'simple_psf_twodhiststats_std.pdf'),
            'reducing_function': 'np.std',
            'number_bins_u': 3,
            'number_bins_v': 3,
        },
    ]

    os.remove(psf_file)
    os.remove(rho_psf_file)
    os.remove(shape_psf_file)
    piff.piffify(config, logger)

    # Test using the piffify executable
    os.remove(psf_file)
    os.remove(rho_psf_file)
    os.remove(shape_psf_file)
    config['verbose'] = 0
    with open('simple.yaml', 'w') as f:
        f.write(yaml.dump(config, default_flow_style=False))
    p = subprocess.Popen([piffify_exe, 'simple.yaml'])
    p.communicate()
コード例 #9
0
def test_chisq():
    """Test the Chisq outlier class
    """
    if __name__ == '__main__':
        logger = piff.config.setup_logger(verbose=2)
    else:
        logger = piff.config.setup_logger(
            log_file='output/test_single_image.log')

    # Make the image
    image = galsim.Image(512, 512, scale=0.26)

    nstars = 1000  # enough that there could be some overlaps.  Also, some over the edge.
    rng = np.random.RandomState(1234)
    x = rng.random_sample(nstars) * 512
    y = rng.random_sample(nstars) * 512
    sigma = np.ones_like(x) * 0.4  # Most have this sigma
    g1 = np.ones_like(x) * 0.023  # Most are pretty round.
    g2 = np.ones_like(x) * 0.012
    flux = np.exp(rng.normal(size=nstars))
    print('flux range = ', np.min(flux), np.max(flux), np.median(flux),
          np.mean(flux))

    # Make a few intentionally wrong.
    g1[35] = 0.29
    g1[188] = -0.15
    sigma[239] = 0.2
    g2[347] = -0.15
    sigma[551] = 1.3
    g2[809] = 0.05
    g1[922] = -0.03

    # Draw a Gaussian PSF at each location on the image.
    for i in range(nstars):
        psf = galsim.Gaussian(sigma=sigma[i]).shear(g1=g1[i], g2=g2[i])
        stamp = psf.drawImage(scale=0.26, center=galsim.PositionD(x[i], y[i]))
        b = stamp.bounds & image.bounds
        image[b] += stamp[b]

    noise = 0.02
    image.addNoise(
        galsim.GaussianNoise(rng=galsim.BaseDeviate(1234), sigma=noise))

    image_file = os.path.join('output', 'test_chisq_im.fits')
    image.write(image_file)

    # Write out the catalog to a file
    dtype = [('x', 'f8'), ('y', 'f8')]
    data = np.empty(len(x), dtype=dtype)
    data['x'] = x
    data['y'] = y
    cat_file = os.path.join('output', 'test_chisq_cat.fits')
    fitsio.write(cat_file, data, clobber=True)

    # Read the catalog in as stars.
    config = {
        'image_file_name': image_file,
        'cat_file_name': cat_file,
        'noise': noise**2,  # Variance here is sigma^2
        'stamp_size': 15,
        'use_partial': True,
    }
    input = piff.InputFiles(config, logger=logger)
    stars = input.makeStars()

    # Skip the solve step.  Just give it the right answer and see what it finds for outliers
    model = piff.Gaussian()
    interp = piff.Mean()
    interp.mean = np.array([0.4, 0.023, 0.012])
    psf = piff.SimplePSF(model, interp)
    stars = psf.interpolateStarList(stars)
    stars = [psf.model.reflux(s, logger=logger) for s in stars]

    outliers1 = piff.ChisqOutliers(nsigma=5)
    stars1, nremoved1 = outliers1.removeOutliers(stars, logger=logger)
    print('nremoved1 = ', nremoved1)
    assert len(stars1) == len(stars) - nremoved1

    # This is what nsigma=5 means in terms of probability
    outliers2 = piff.ChisqOutliers(prob=5.733e-7)
    stars2, nremoved2 = outliers2.removeOutliers(stars, logger=logger)
    print('nremoved2 = ', nremoved2)
    assert len(stars2) == len(stars) - nremoved2
    assert nremoved1 == nremoved2

    # The following is nearly equivalent for this particular data set.
    # For dof=222 (what most of these have, this probability converts to
    # thresh = 455.40143379
    # or ndof = 2.0513578
    # But note that when using the above prop or nsigma, the code uses a tailored threshold
    # different for each star's particular dof, which varies (since some are off the edge).
    outliers3 = piff.ChisqOutliers(thresh=455.401)
    stars3, nremoved3 = outliers3.removeOutliers(stars, logger=logger)
    print('nremoved3 = ', nremoved3)
    assert len(stars3) == len(stars) - nremoved3

    outliers4 = piff.ChisqOutliers(ndof=2.05136)
    stars4, nremoved4 = outliers4.removeOutliers(stars, logger=logger)
    print('nremoved4 = ', nremoved4)
    assert len(stars4) == len(stars) - nremoved4
    assert nremoved3 == nremoved4

    # Regression tests.  If these change, make sure we understand why.
    assert nremoved1 == nremoved2 == 58
    assert nremoved3 == nremoved4 == 16  # Much less, since edge objects aren't being removed
    # nearly as often as when they have a custom thresh.

    # Can't provide multiple thresh specifications
    np.testing.assert_raises(TypeError,
                             piff.ChisqOutliers,
                             nsigma=5,
                             prob=1.e-3)
    np.testing.assert_raises(TypeError,
                             piff.ChisqOutliers,
                             nsigma=5,
                             thresh=100)
    np.testing.assert_raises(TypeError, piff.ChisqOutliers, nsigma=5, ndof=3)
    np.testing.assert_raises(TypeError,
                             piff.ChisqOutliers,
                             prob=1.e-3,
                             thresh=100)
    np.testing.assert_raises(TypeError, piff.ChisqOutliers, prob=1.e-3, ndof=3)
    np.testing.assert_raises(TypeError, piff.ChisqOutliers, thresh=100, ndof=3)

    # Need to specifiy it somehow.
    np.testing.assert_raises(TypeError, piff.ChisqOutliers)