Apply the reduction method in the appendix of Scholtus (2008) to a matrix.
Let A with coefficients in {-1,0,1}. If, after a possible
permutation of columns it can be written
in the form A=[B,C] where each column in B has at most 1 nonzero
element, then A is totally unimodular if and only if C is totally
unimodular. By transposition, a similar theorem holds for the rows of A. This
function iteratively removes rows and columns with only 1 nonzero element
from A and returns the reduced result.
Usage
reduceMatrix(A)
Arguments
A
An object of class matrix in {-1,0,1}^{m\times n}.
Value
The reduction of A.
References
Scholtus S (2008). Algorithms for correcting some obvious
inconsistencies and rounding errors in business survey data. Technical
Report 08015, Netherlands.