source_selector

class txpipe.source_selector.TXSourceSelector(*args: Any, **kwargs: Any)

Bases: ceci.

This pipeline stage selects objects to be used as the source sample for the shear-shear and shear-position calibrations. It applies some general cuts based on the flags that metacal gives for the objects, and size and S/N cuts based on the configuration file.

It also splits those objects into tomographic bins according to the choice the user makes in the input file, from the information in the photo-z PDF file.

Once these selections are made it constructs the quantities needed to calibrate each bin - this consists of two shear response quantities.

TODO: add option to use lensfit catalogs, which would be much much simpler.

apply_classifier(classifier, features, shear_data)

Apply the classifier to the measured magnitudes

calculate_tomography(pz_data, shear_data, calibrators)

Select objects to go in each tomographic bin and their calibration.

Parameters

• pz_data (table or dict of arrays) – A chunk of input photo-z data containing mean values for each object

• shear_data (table or dict of arrays) – A chunk of input shear data with metacalibration variants.

run()

Run the analysis for this stage.

• Collect the list of columns to read

• Create iterators to read chunks of those columns

• Loop through chunks:

  • select objects for each bin

  • write them out

  • accumulate selection bias values

• Average the selection biases

• Write out biases and close the output

setup_output()

Set up the output data file.

Creates the data sets and groups to put module output in the shear_tomography_catalog output file.

write_global_values(outfile, calibrators, number_density_stats)

Write out overall selection biases

Parameters

• outfile (h5py.File) –

• S (array of shape (nbin,2,2)) – Selection bias matrices

write_tomography(outfile, start, end, source_bin, R)

Write out a chunk of tomography and response.

Parameters

• outfile (h5py.File) –

• start (int) – The index into the output this chunk starts at

• end (int) – The index into the output this chunk ends at

• tomo_bin (array of shape (nrow,)) – The bin index for each output object

• R (array of shape (nrow,2,2)) – Multiplicative bias calibration factor for each object