hpmcm.shear_match module

class hpmcm.shear_match.ShearMatch(**kwargs)[source]

Class to do N-way matching for shear calibration.

Uses pre-assigned pixel locations from cell-based coadd WCS.

Since the pixel locations and cells are pre-assigned, the only configurable parameters this class takes are the attributres listed here.

The pixel_match_scale can we used to allow for matching sources that are seperate by more that 1 pixel.

Expects 5 input catalogs: a reference catalog and 4 counterfactual shear catalogs.

pixel_match_scale

Number of pixels to merge in original counts map

cat_type

Shear catalog type

deshear

Deshearing parameter, -1*applied shear. None -> deshearing is not done.

Notes

This expectes a list of parquet files with pandas DataFrames that contain the following columns.

Column name	Description
id	source ID
tract	Tract being matched
x_cell_coadd	X-postion in cell-based coadd used for metadetect
y_cell_coadd	Y-postion in cell-based coadd used for metadetect
snr	Signal-to-Noise of source, used for filtering and centroiding
cell_idx_x	Cell x-index within Tract
cell_idx_y	Cell y-index within Tract
g_1	Shear g1 component
g_2	Shear g1 component

These parquet files can be generated from files with the following columns using the ShearMatch.splitByTypeAndClean() function.

Column name	Description
id	source ID
shear_type	one of “ns”, “1p”, “1m”, “2p” “2m”
patch_{x,y}	id of the patch within the tract
cell_{x,y}	id of the cell withing the patch
snr	Signal-to-Noise of source
{cat_type}_band_flux_{band}	Flux measuremnt in the reference band
{cat_type}_band_flux_err_{band}	Flux error in the reference band
{cat_type}_g_{i}	Shear measurements

Two additional tables are produced beyond the tables produced by the base hpmcm.Match class

Key	Class
_object_shear	`hpmcm.output_tables.ShearTable`
_cluster_shear	`hpmcm.output_tables.ShearTable`

classmethod createShearMatch(**kwargs)[source]

Helper function to create a ShearMatch object

This will use the use pixel-coordinates read from the input shear tables.

Return type:: ShearMatch
Parameters:: kwargs (Any) – Passed directly to ShearMatch constructor.
Return type:: Object to create matches for the requested region

extractShearStats()[source]

Extract shear stats

Theis will produce two hpmcm.output_tables.ShearTable, one for the objects, and the other for the clusters.

getCellIndices(df)[source]

Get the cell index assocatiated to each source

reduceDataFrame(df)[source]

Reduce a single input DataFrame

Notes

This applies a trivial cut on signal-to-noise (snr>1).

This will add these columns to the output dataframes

Column	Description
id	Index of object inside catalog
ra	Source RA
dec	Source DEC
cell_idx_x	X-index of Cell
cell_idx_y	Y-index of Cell
x_cell_coadd	X-coordinate in cell frame
y_cell_coadd	Y-coordinate in cell frame
x_pix	X-coordinate in global WCS frame
y_pix	Y-coordinate in global WCS frame
g_1	Shear g_1 component estimate
g_2	Shear g_2 component estimate
snr	Signal-to-noise ratio