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, considerable 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

• The column domain and row domain are of the same cardinality.



• Each column has exactly one entry.



• 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.