COLAMD, Copyright 1998-2012, Timothy A. Davis. http://www.suitesparse.com
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The COLAMD column approximate minimum degree ordering algorithm computes
a permutation vector P such that the LU factorization of A (:,P)
tends to be sparser than that of A. The Cholesky factorization of
(A (:,P))'*(A (:,P)) will also tend to be sparser than that of A'*A.
SYMAMD is a symmetric minimum degree ordering method based on COLAMD,
available as a MATLAB-callable function. It constructs a matrix M such
that M'*M has the same pattern as A, and then uses COLAMD to compute a column
ordering of M. Colamd and symamd tend to be faster and generate better
orderings than their MATLAB counterparts, colmmd and symmmd.
To compile and test the colamd m-files and mexFunctions, just unpack the
COLAMD/ directory from the COLAMD.tar.gz file, and run MATLAB from
within that directory. Next, type colamd_test to compile and test colamd
and symamd. This will work on any computer with MATLAB (Unix, PC, or Mac).
Alternatively, type "make" (in Unix) to compile and run a simple example C
code, without using MATLAB.
To compile and install the colamd m-files and mexFunctions, just cd to
COLAMD/MATLAB and type colamd_install in the MATLAB command window.
A short demo will run. Optionally, type colamd_test to run an extensive tests.
Type "make" in Unix in the COLAMD directory to compile the C-callable
library and to run a short demo.
Colamd is a built-in routine in MATLAB, available from The
Mathworks, Inc. Under most cases, the compiled COLAMD from Versions 2.0 to the
current version do not differ. Colamd Versions 2.2 and 2.3 differ only in their
mexFunction interaces to MATLAB. v2.4 fixes a bug in the symamd routine in
v2.3. The bug (in v2.3 and earlier) has no effect on the MATLAB symamd
mexFunction. v2.5 adds additional checks for integer overflow, so that
the "int" version can be safely used with 64-bit pointers. Refer to the
ChangeLog for more details.
To use colamd and symamd within an application written in C, all you need are
colamd.c, colamd_global.c, and colamd.h, which are the C-callable
colamd/symamd codes. See colamd.c for more information on how to call
colamd from a C program.
Requires SuiteSparse_config, in the ../SuiteSparse_config directory relative to
this directory.
See the colamd.c file or http://www.suitesparse.com for the license to COLAMD.
Related papers:
T. A. Davis, J. R. Gilbert, S. Larimore, E. Ng, An approximate column
minimum degree ordering algorithm, ACM Transactions on Mathematical
Software, vol. 30, no. 3., pp. 353-376, 2004.
T. A. Davis, J. R. Gilbert, S. Larimore, E. Ng, Algorithm 836: COLAMD,
an approximate column minimum degree ordering algorithm, ACM
Transactions on Mathematical Software, vol. 30, no. 3., pp. 377-380,
2004.
"An approximate minimum degree column ordering algorithm",
S. I. Larimore, MS Thesis, Dept. of Computer and Information
Science and Engineering, University of Florida, Gainesville, FL,
1998. CISE Tech Report TR-98-016.
Approximate Deficiency for Ordering the Columns of a Matrix,
J. L. Kern, Senior Thesis, Dept. of Computer and Information
Science and Engineering, University of Florida, Gainesville, FL,
1999.
Authors: Stefan I. Larimore and Timothy A. Davis,
in collaboration with John Gilbert, Xerox PARC (now at UC Santa Barbara),
and Esmong Ng, Lawrence Berkeley National Laboratory (much of this work
he did while at Oak Ridge National Laboratory).
COLAMD files:
Demo simple demo
Doc additional documentation (see colamd.c for more)
Include include file
Lib compiled C-callable library
Makefile primary Unix Makefile
MATLAB MATLAB functions
README.txt this file
Source C source code
./Demo:
colamd_example.c simple example
colamd_example.out output of colamd_example.c
colamd_l_example.c simple example, long integers
colamd_l_example.out output of colamd_l_example.c
Makefile Makefile for C demos
./Doc:
ChangeLog change log
lesser.txt license
./Include:
colamd.h include file
./Lib:
Makefile Makefile for C-callable library
./MATLAB:
colamd2.m MATLAB interface for colamd2
colamd_demo.m simple demo
colamd_install.m compile and install colamd2 and symamd2
colamd_make.m compile colamd2 and symamd2
colamdmex.ca MATLAB mexFunction for colamd2
colamd_test.m extensive test
colamdtestmex.c test function for colamd
Contents.m contents of the MATLAB directory
luflops.m test code
Makefile Makefile for MATLAB functions
symamd2.m MATLAB interface for symamd2
symamdmex.c MATLAB mexFunction for symamd2
symamdtestmex.c test function for symamd
./Source:
colamd.c primary source code
colamd_global.c globally defined function pointers (malloc, free, ...)