Previous: zlauu2 Up: ../lapack-z.html Next: zlazro

zlauum

 NAME
      ZLAUUM - compute the product U * U' or L' * L, where the
      triangular factor U or L is stored in the upper or lower
      triangular part of the array A

 SYNOPSIS
      SUBROUTINE ZLAUUM( UPLO, N, A, LDA, INFO )

          CHARACTER      UPLO

          INTEGER        INFO, LDA, N

          COMPLEX*16     A( LDA, * )

 PURPOSE
      ZLAUUM computes the product U * U' or L' * L, where the tri-
      angular factor U or L is stored in the upper or lower tri-
      angular part of the array A.

      If UPLO = 'U' or 'u' then the upper triangle of the result
      is stored, overwriting the factor U in A.
      If UPLO = 'L' or 'l' then the lower triangle of the result
      is stored, overwriting the factor L in A.

      This is the blocked form of the algorithm, calling Level 3
      BLAS.

 ARGUMENTS
      UPLO    (input) CHARACTER*1
              Specifies whether the triangular factor stored in
              the array A is upper or lower triangular:
              = 'U':  Upper triangular
              = 'L':  Lower triangular

      N       (input) INTEGER
              The order of the triangular factor U or L.  N >= 0.

      A       (input/output) COMPLEX*16 array, dimension (LDA,N)
              On entry, the triangular factor U or L.  On exit, if
              UPLO = 'U', the upper triangle of A is overwritten
              with the upper triangle of the product U * U'; if
              UPLO = 'L', the lower triangle of A is overwritten
              with the lower triangle of the product L' * L.

      LDA     (input) INTEGER
              The leading dimension of the array A.  LDA >=
              max(1,N).

      INFO    (output) INTEGER
              = 0: successful exit
              < 0: if INFO = -k, the k-th argument had an illegal

              value