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
- fftw3 library:
fftw3 >= 3.3.3
Parallel run
- MPI library
- 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.