Description

A library to compute the 3D and angular correlation function using MPI. Data and random points are distributed over domains, and pairs are calculated within and across domains. A fast serial implementation can be found on the Corrfunc webpage

Installation

Pre-requisities

Serial run

1. fftw3 library: fftw3 >= 3.3.3

Parallel run

1. MPI library
2. fftw3 & fftw3-mpi library: fftw3 >= 3.3.3

FFTW3

Go to the FFTW webpage <http://www.fftw.org/download.html> to install fftw3. Ensure to compile the library with the enable-mpi flag for parallel runs

$ ./configure --enable-mpi
$ make
$ make install

Note: To create the dynamic libraries, run configure with the --enable-shared flag.

Download & Build

$ git clone https://github.com/annehutter/pcf.git
$ make

This will download the code and first test case from the github directory and compile the source code.

Execution

The first test case can then be run by

$ mpiexec -np #PROCESSORS ./pcf

Functions

The library contains currently three functions:

• calc_3Dcorrfunc_cartesian (int numPoints, double* x, double* y, double* z, boxparams_t* thisBoxparams, domain_t* thisDomain, char* outputName): computes the 3D correlation function from a list of x, y, z coordinates.
• calc_ACF_cartesian (int numPoints, double* x, double* y, double* z, boxparams_t* thisBoxparams, cosmparams_t* thisCosmparams, domain_t* thisDomain, char* outputName): computes the angular correlation function for the box or a set of points located at redshift z from a list of x, y, z coordinates.
• calc_ACF_ra_dec (int numPoints, double* cosTheta, double* phi, boxparams_t* thisBoxparams, cosmparams_t* thisCosmparams, domain_t* thisDomain, char* outputName): computes the angular correlation function for the box or a set of points located at redshift z from a list of cos(theta), phi coordinates.

These functions require as input the number of points, double arrays of the x, y, z coordinates, and the following structs:

• boxparams_t: contains the box measurements, i.e. also galaxies in a subbox can be chosen.
• cosmparams_t: contains the cosmological parameters and redshift where the box or set of point are located. This is only required for the angular correlation function.
• domain_t: contains the domain decomposition. Currently the domain decomposition agrees with those in FFTW, i.e. slicing the box along the z-axis.

Examples how these structs are initialised and used are in the example main.c.