reduceMatrix {deducorrect}

Apply reduction method from Scholtus (2008)

Description

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.

See Also

isTotallyUnimodular