ALTERNATIVE METHODS OF CALCULATION OF THE PSEUDO INVERSE OF A NON FULL-RANK MATRIX

The calculation of the pseudo inverse of a matrix is intimately related to the singular value decomposition which applies to any matrix be it singular or not and square or not. The matrices involved in the singular value decomposition of a matrix A are formed with the orthogonal eigen vectors of the...

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Bibliographic Details
Author: M. A. Murray-Lasso
Format: article
Status:Published version
Publication Date:2008
Country:México
Institution:Universidad Nacional Autónoma de México
Repository:Redalyc-UNAM
OAI Identifier:oai:redalyc.org:47413023004
Online Access:https://www.redalyc.org/articulo.oa?id=47413023004
Access Level:Open access
Keyword:Ingeniería
least
length
squares
minimum
Pseudo inverse
Description
Summary:The calculation of the pseudo inverse of a matrix is intimately related to the singular value decomposition which applies to any matrix be it singular or not and square or not. The matrices involved in the singular value decomposition of a matrix A are formed with the orthogonal eigen vectors of the symmetric matrices ATA and AAT associated with their nonzero eigenvalues which forms a diagonal matrix. If instead of using the eigenvectors, which are difficult to calculate, we use any set of vectors that span the same spaces, which are easier to obtain, we can get simpler expressions for calculating the pseudoinverse, although the diagonal matrix of eigenvalues is filled. All numerical work to obtain the pseudo inverse whose components are rational numbers when the original matrix is also rational reduces to elementary row operations. We can, thus, generalize the least-squares/ minimum length normal equations for full-rank matrices and solve said problems and obtain the pseudo inverse in terms of A and AT. without solving any eigen problems or factoring matrices.