.TH "elpa_cholesky_real" 3 "Wed Jun 29 2016" "ELPA" \" -*- nroff -*-
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.SH NAME
elpa_cholesky_real \- Cholesky factorization of a real symmetric matrix
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.SH SYNOPSIS
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.SS FORTRAN INTERFACE
use elpa1
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.RI  "success = \fBelpa_cholesky_real\fP (na, a(lda,matrixCols), lda, nblk, matrixCols, mpi_comm_rows, mpi_comm_cols, wantDebug)"
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.RI " "
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.RI "With the definintions of the input and output variables:"

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.RI "integer, intent(in)    \fBna\fP:            global dimension of quadratic matrix \fBa\fP to solve"
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.RI "real*8,  intent(inout) \fBa\fP:             locally distributed part of the matrix \fBa\fP. The local dimensions are \fBlda\fP x \fBmatrixCols\fP"
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.RI "integer, intent(in)    \fBlda\fP:           leading dimension of locally distributed matrix \fBa\fP"
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.RI "integer, intent(in)    \fBnblk\fP:          blocksize of cyclic distribution, must be the same in both directions"
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.RI "integer, intent(in)    \fBmatrixCols\fP:    number of columns of locally distributed matrices \fBa\fP and \fBq\fP"
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.RI "integer, intent(in)    \fBmpi_comm_rows\fP: communicator for communication in rows. Constructed with \fBelpa_get_communicators\fP(3)"
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.RI "integer, intent(in)    \fBmpi_comm_cols\fP: communicator for communication in colums. Constructed with \fBelpa_get_communicators\fP(3)"
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.RI "logical, intent(in)    \fBwantDebug\fP:     if .true. , print more debug information in case of an error"

.RI "logical                \fBsuccess\fP:       return value indicating success or failure"
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.SS C INTERFACE
#include "elpa.h"

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.RI "\fBint\fP success = \fBelpa_cholesky_real\fP (\fBint\fP na, \fB double *\fPa, \fBint\fP lda, \fBint\fP nblk, \fBint\fP matrixCols, \fBint\fP mpi_comm_rows, \fBint\fP mpi_comm_cols, \fBint\fP wantDebug );"
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.RI " "
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.RI "With the definintions of the input and output variables:"

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.RI "int     \fBna\fP:            global dimension of quadratic matrix \fBa\fP to solve"
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.RI "double *\fBa\fP:             pointer to locally distributed part of the matrix \fBa\fP. The local dimensions are \fBlda\fP x \fBmatrixCols\fP"
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.RI "int     \fBlda\fP:           leading dimension of locally distributed matrix \fBa\fP"
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.RI "int     \fBnblk\fP:          blocksize of block cyclic distributin, must be the same in both directions"
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.RI "int     \fBmatrixCols\fP:    number of columns of locally distributed matrices \fBa\fP and \fBq\fP"
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.RI "int     \fBmpi_comm_rows\fP: communicator for communication in rows. Constructed with \fBelpa_get_communicators\fP(3)"
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.RI "int     \fBmpi_comm_cols\fP: communicator for communication in colums. Constructed with \fBelpa_get_communicators\fP(3)"
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.RI "int     \fBwantDebug\fP:     if 1, print more debug information in case of an error"
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.RI "int     \fBsuccess\fP:       return value indicating success (1) or failure (0)

.SH DESCRIPTION
Does a Cholesky factorization of a real, symmetric matrix. The ELPA communicators \fBmpi_comm_rows\fP and \fBmpi_comm_cols\fP are obtained with the \fBelpa_get_communicators\fP(3) function. The distributed quadratic marix \fBa\fP has global dimensions \fBna\fP x \fBna\fP, and a local size \fBlda\fP x \fBmatrixCols\fP.
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.SH "SEE ALSO"
\fBelpa_get_communicators\fP(3) \fBelpa_cholesky_real\fP(3)