load_nz_sacc
================================================

Load number density n(z) from a SACC file for weak lensing

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| File        | number_density/load_nz_sacc/load_nz_sacc.py |
+-------------+---------------------------------------------+
| Attribution | CosmoSIS Team                               |
+-------------+---------------------------------------------+
| URL         |                                             |
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This module loads number density n(z) distributions from a SACC (Save All 
Correlations and Covariances) file format. SACC is a standard format for storing
cosmological survey data including n(z) information.

The module searches for tracers matching the specified data set names and
extracts their redshift distributions. It validates that all bins use the
same redshift grid and outputs the data in CosmoSIS format.


Assumptions
-----------

 - SACC file contains n(z) tracer data
 - All bins have the same redshift grid



Setup Parameters
----------------

.. list-table::
   :header-rows: 1

   * - Name
     - Type
     - Default
     - Description

   * - nz_file
     - str
     - 
     - Path to the SACC file containing n(z) data
   * - data_sets
     - str
     - 
     - Space-separated list of tracer names to search for in SACC file
   * - prefix_section
     - bool
     - True
     - Whether to prefix output section names with 'nz_'


Input values
----------------

None


Output values
----------------


.. list-table:: Output values
   :header-rows: 1

   * - Section
     - Name
     - Type
     - Description

   * - nz_{data_set}
     - nbin
     - int
     - Number of redshift bins
   * - 
     - nz
     - int
     - Number of redshift samples
   * - 
     - z
     - real 1d
     - Redshift sample values
   * - 
     - bin_{i}
     - real 1d
     - n(z) values for bin i (bin_1, bin_2, ...)