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Optimized LAPACK Functions

This section describes all function families in the optimized LAPACK.

Feature

Function Family

Data Type

Description

Matrix factorization

?getrf

s, d, c, z

Matrix LU factorization, allowing row interchanges.

?geqrf

s, d, c, z

Matrix QR factorization.

?gerqf

s, d, c, z

Matrix RQ factorization.

?geqlf

s, d, c, z

Matrix QL factorization.

?gelqf

s, d, c, z

Matrix LQ factorization.

?potrf

s, d, c, z

Cholesky factorization of a real symmetric or conjugate symmetric positive definite matrix.

?pttrf

s, d, c, z

LDL* or U*DU factorization of a real (conjugate) symmetric positive definite tridiagonal matrix A.

?gttrf

s, d, c, z

LU factorization of general tridiagonal matrix A.

?sptrf

s, d, c, z

LDL* or U*DU factorization of a packed symmetric matrix.

?pptrf

s, d, c, z

LLT or UTU factorization of a symmetric positive definite matrix in packed storage.

Linear equation systems solving

?ppsv

s, d, c, z

Cholesky factorization of a positive definite matrix in packed storage with real symmetry or conjugate symmetry.

?gesv

s, d, c, z

Solves the system of linear equations using the result of LU factorization.

?ptsv

s, d, c, z

Solve a system of linear equations, in which the coefficient matrix A is a real (conjugate) symmetric positive definite tridiagonal matrix.

?gtsv

s, d, c, z

Solves the system of linear equations A * X = B, where A is a general tridiagonal coefficient matrix.

?posv

s, d, c, z

Solves the system of linear equations A * X = B, where A is a real or conjugate symmetric positive definite coefficient matrix.

Matrix inversion

?getri

s, d, c, z

Computes the inverse matrix based on the ?getrf result.

?potri

s, d, c, z

Computes the inverse matrix based on the ?potrf result.

?pptri

s, d, c, z

Computes the inverse matrix based on the ?pptrf result.

?trtri

s, d, c, z

Computes the inverse matrix of an upper/lower triangular matrix.

Back substitution solution

?pttrs

s, d, c, z

Solves the tridiagonal equation AX = B, where the coefficient matrix A is the ?pttrf factorization result.

?ptts2

s, d, c, z

Solves the tridiagonal equation AX = B, where the coefficient matrix A is the ?pttrf factorization result.

?gttrs

s, d, c, z

Solves the tridiagonal equation A * X = B, AT * X = B, or AH * X = B, where coefficient matrix A is the ?gttrf factorization result.

?trtrs

s, d, c, z

Solves the trigonometric equation A * X = B or AT * X = B.

?getrs

s, d, c, z

Solves the general linear equation AX = B, where the coefficient matrix A is the ?getrf factorization result.

?pptrs

s, d, c, z

Solves packed symmetric positive definite linear equation AX = B, where the coefficient matrix A is the ?pptrf factorization result.

Eigenvalue problem solving

?sy(he)evd

s, d, c, z

Computes the eigenvalues and eigenvectors of a real symmetric (Hermitian) matrix. The eigenvectors are computed using a divide and conquer algorithm.

?sy(he)ev

s, d, c, z

Computes the eigenvalues and eigenvectors of a real symmetric (Hermitian) matrix.

Others

?(or,un)glq

s, d, c, z

Generates a real or complex matrix Q with orthogonal rows, where H for calculating Q is obtained by calling ?gelqf.

?(or,un)gqr

s, d, c, z

Generates a real or complex matrix Q with orthogonal rows, where H for calculating Q is obtained by calling ?geqrf.

?(or,un)grq

s, d, c, z

Generates a real or complex matrix Q with orthogonal rows, where H for calculating Q is obtained by calling ?gerqf.

?(or,un)gql

s, d, c, z

Generates a real or complex matrix Q with orthogonal columns, where H for calculating Q is obtained by calling ?geqlf.

?(or,un)mlq

s, d, c, z

Computes or , where Q is returned by ?gelqf. Q* can be QT or QH.

?(or,un)mqr

s, d, c, z

Computes or , where Q is returned by ?geqrf. Q* can be QT or QH.

?(or,un)mql

s, d, c, z

Computes or , where Q is returned by ?geqlf. Q* can be QT or QH.

?(or,un)mrq

s, d, c, z

Computes or , where Q is returned by ?gerqf. Q* can be QT or QH.

?sy(he)trd

s, d, c, z

Transforms a symmetric or Hermitian matrix to symmetric tridiagonal matrix T by means of similarity transformation.

?sy(he)trd_2stage

s, d, c, z

Transforms symmetric matrix A to symmetric tridiagonal matrix T. That is, AT * A * Q = T, where Q is an orthogonal matrix.

?lasr

s, d, c, z

Performs a plane rotation operation on matrix A.

Auxiliary functions

?laset

s, d, c, z

Initializes an m*n matrix and sets the diagonal elements to beta and the non-diagonal elements to alpha.

?laswp

s, d, c, z

Perform a series of row exchange operations on a matrix.

?lascl

s, d, c, z

Performs scalar operations on a matrix.

?lange

s, d, c, z

Computes the norms of a matrix (including 1-norm, F-norm, and infinite norm).