mcxmap(1) USER COMMANDS mcxmap(1)
NAME
mcxmap - permute or remap the indices of graphs and matrices.
SYNOPSIS
mcxmap -imx fname (input) [-o fname (output)] [-make-map (output map file name)] [-make-mapc (output map file name)] [-make-mapr (output map
file name)] [-cmul a (coefficient)] [-cshift b (translate)] [-rmul c (coefficient)] [-rshift d (translate)] [-mul e (coefficient)] [-shift f
(translate)] [-map fname (row/col map file)] [-rmap fname (row map file)] [-cmap fname (column map file)] [-mapi fname (row/col map file
(use inverse))] [-rmapi fname (row map file (use inverse))] [-cmapi fname (column map file (use inverse))] [-tab fname (read (and map) tab
file)]
DESCRIPTION
This utility relabels graphs or matrices. Its main use is in applying a map file to a given matrix or graph. A map file contains a so called
map matrix in mcl format that has some special properties (given further below). The functionality of mcxmap can also be provided by mcx, as
a mapped matrix (i.e. the result of applying a map matrix to another matrix) is simply the usual matrix product of a matrix and a map
matrix. However, mcx will construct a new matrix and leave the original matrix to be mapped alone. When dealing with huge matrices, consid-
erable gains in efficiency memory-wise and time-wise can be achieved by doing the mapping in-place. This is what mcxmap does. In the
future, its functionality may be embedded in mcx with new mcx operators.
The special properties of a map matrix are
o The column domain and row domain are of the same cardinality.
o Each column has exactly one entry.
o Each row domain index occurs in exactly one column.
These properties imply that the matrix can be used as a map from the column domain onto the row domain. An example map matrix is found in
the EXAMPLES Section.
OPTIONS
-o fname (output file)
Output file.
-imx fname (input file)
Input file.
-map fname (row/col map file))
-rmap fname (row map file)
-cmap fname (column map file)
-mapi fname (row/col map file (use inverse))
-rmapi fname (row map fil (use inverse))
-cmapi fname (column map fil (use inverse))
Different ways to specify map files.
-make-map (output map file name)
-make-mapc (output map file name)
-make-mapr (output map file name)
Generate a map that maps the specified domain onto the appropriate canonical domain and write the map matrix to file.
-cmul a (coefficient)
-cshift b (translate)
These options have affect if neither a column map file nor column canonification is specified. If any of the first two options is used,
column indices i are mapped to a*i+b.
-rmul c (coefficient)
-rshift d (translate)
These options have affect if neither a row map file nor row canonification is specified. If any of the first two options is used,
indices i are mapped to c*i+d.
-mul e (coefficient)
-shift f (translate)
If a map file is specified for a given domain, neither a map file nor canonification is specified. If any of the first two options is
used, the indices i will be mapped to e*i+f.
-tab fname (read (and map) tab file)
This option requires the -map option. mcxmap will output the mapped tab definition.
EXAMPLES
The matrix below has two canonical domains which are identical. It denotes a map of the canonical domain onto itself, in which node 0 is
relabeled to 8, node 1 is relabeled to 5, et cetera.
(mclheader
mcltype matrix
dimensions 12x12
)
(mclmatrix
begin
0 8 $
1 5 $
2 3 $
3 2 $
4 4 $
5 6 $
6 7 $
7 9 $
8 1 $
9 10 $
10 11 $
11 0 $
)
AUTHOR
Stijn van Dongen.
SEE ALSO
mcxio(5), mcx(1), mcxsubs(1), and mclfamily(7) for an overview of all the documentation and the utilities in the mcl family.
mcxmap 12-068 8 Mar 2012 mcxmap(1)