Provided by: liblapack-doc_3.12.0-3build1.1_all bug

NAME

       ungql - {un,or}gql: generate explicit Q from geqlf

SYNOPSIS

   Functions
       subroutine cungql (m, n, k, a, lda, tau, work, lwork, info)
           CUNGQL
       subroutine dorgql (m, n, k, a, lda, tau, work, lwork, info)
           DORGQL
       subroutine sorgql (m, n, k, a, lda, tau, work, lwork, info)
           SORGQL
       subroutine zungql (m, n, k, a, lda, tau, work, lwork, info)
           ZUNGQL

Detailed Description

Function Documentation

   subroutine cungql (integer m, integer n, integer k, complex, dimension( lda, * ) a, integer
       lda, complex, dimension( * ) tau, complex, dimension( * ) work, integer lwork, integer
       info)
       CUNGQL

       Purpose:

            CUNGQL generates an M-by-N complex matrix Q with orthonormal columns,
            which is defined as the last N columns of a product of K elementary
            reflectors of order M

                  Q  =  H(k) . . . H(2) H(1)

            as returned by CGEQLF.

       Parameters
           M

                     M is INTEGER
                     The number of rows of the matrix Q. M >= 0.

           N

                     N is INTEGER
                     The number of columns of the matrix Q. M >= N >= 0.

           K

                     K is INTEGER
                     The number of elementary reflectors whose product defines the
                     matrix Q. N >= K >= 0.

           A

                     A is COMPLEX array, dimension (LDA,N)
                     On entry, the (n-k+i)-th column must contain the vector which
                     defines the elementary reflector H(i), for i = 1,2,...,k, as
                     returned by CGEQLF in the last k columns of its array
                     argument A.
                     On exit, the M-by-N matrix Q.

           LDA

                     LDA is INTEGER
                     The first dimension of the array A. LDA >= max(1,M).

           TAU

                     TAU is COMPLEX array, dimension (K)
                     TAU(i) must contain the scalar factor of the elementary
                     reflector H(i), as returned by CGEQLF.

           WORK

                     WORK is COMPLEX array, dimension (MAX(1,LWORK))
                     On exit, if INFO = 0, WORK(1) returns the optimal LWORK.

           LWORK

                     LWORK is INTEGER
                     The dimension of the array WORK. LWORK >= max(1,N).
                     For optimum performance LWORK >= N*NB, where NB is the
                     optimal blocksize.

                     If LWORK = -1, then a workspace query is assumed; the routine
                     only calculates the optimal size of the WORK array, returns
                     this value as the first entry of the WORK array, and no error
                     message related to LWORK is issued by XERBLA.

           INFO

                     INFO is INTEGER
                     = 0:  successful exit
                     < 0:  if INFO = -i, the i-th argument has an illegal value

       Author
           Univ. of Tennessee

           Univ. of California Berkeley

           Univ. of Colorado Denver

           NAG Ltd.

   subroutine dorgql (integer m, integer n, integer k, double precision, dimension( lda, * ) a,
       integer lda, double precision, dimension( * ) tau, double precision, dimension( * ) work,
       integer lwork, integer info)
       DORGQL

       Purpose:

            DORGQL generates an M-by-N real matrix Q with orthonormal columns,
            which is defined as the last N columns of a product of K elementary
            reflectors of order M

                  Q  =  H(k) . . . H(2) H(1)

            as returned by DGEQLF.

       Parameters
           M

                     M is INTEGER
                     The number of rows of the matrix Q. M >= 0.

           N

                     N is INTEGER
                     The number of columns of the matrix Q. M >= N >= 0.

           K

                     K is INTEGER
                     The number of elementary reflectors whose product defines the
                     matrix Q. N >= K >= 0.

           A

                     A is DOUBLE PRECISION array, dimension (LDA,N)
                     On entry, the (n-k+i)-th column must contain the vector which
                     defines the elementary reflector H(i), for i = 1,2,...,k, as
                     returned by DGEQLF in the last k columns of its array
                     argument A.
                     On exit, the M-by-N matrix Q.

           LDA

                     LDA is INTEGER
                     The first dimension of the array A. LDA >= max(1,M).

           TAU

                     TAU is DOUBLE PRECISION array, dimension (K)
                     TAU(i) must contain the scalar factor of the elementary
                     reflector H(i), as returned by DGEQLF.

           WORK

                     WORK is DOUBLE PRECISION array, dimension (MAX(1,LWORK))
                     On exit, if INFO = 0, WORK(1) returns the optimal LWORK.

           LWORK

                     LWORK is INTEGER
                     The dimension of the array WORK. LWORK >= max(1,N).
                     For optimum performance LWORK >= N*NB, where NB is the
                     optimal blocksize.

                     If LWORK = -1, then a workspace query is assumed; the routine
                     only calculates the optimal size of the WORK array, returns
                     this value as the first entry of the WORK array, and no error
                     message related to LWORK is issued by XERBLA.

           INFO

                     INFO is INTEGER
                     = 0:  successful exit
                     < 0:  if INFO = -i, the i-th argument has an illegal value

       Author
           Univ. of Tennessee

           Univ. of California Berkeley

           Univ. of Colorado Denver

           NAG Ltd.

   subroutine sorgql (integer m, integer n, integer k, real, dimension( lda, * ) a, integer lda,
       real, dimension( * ) tau, real, dimension( * ) work, integer lwork, integer info)
       SORGQL

       Purpose:

            SORGQL generates an M-by-N real matrix Q with orthonormal columns,
            which is defined as the last N columns of a product of K elementary
            reflectors of order M

                  Q  =  H(k) . . . H(2) H(1)

            as returned by SGEQLF.

       Parameters
           M

                     M is INTEGER
                     The number of rows of the matrix Q. M >= 0.

           N

                     N is INTEGER
                     The number of columns of the matrix Q. M >= N >= 0.

           K

                     K is INTEGER
                     The number of elementary reflectors whose product defines the
                     matrix Q. N >= K >= 0.

           A

                     A is REAL array, dimension (LDA,N)
                     On entry, the (n-k+i)-th column must contain the vector which
                     defines the elementary reflector H(i), for i = 1,2,...,k, as
                     returned by SGEQLF in the last k columns of its array
                     argument A.
                     On exit, the M-by-N matrix Q.

           LDA

                     LDA is INTEGER
                     The first dimension of the array A. LDA >= max(1,M).

           TAU

                     TAU is REAL array, dimension (K)
                     TAU(i) must contain the scalar factor of the elementary
                     reflector H(i), as returned by SGEQLF.

           WORK

                     WORK is REAL array, dimension (MAX(1,LWORK))
                     On exit, if INFO = 0, WORK(1) returns the optimal LWORK.

           LWORK

                     LWORK is INTEGER
                     The dimension of the array WORK. LWORK >= max(1,N).
                     For optimum performance LWORK >= N*NB, where NB is the
                     optimal blocksize.

                     If LWORK = -1, then a workspace query is assumed; the routine
                     only calculates the optimal size of the WORK array, returns
                     this value as the first entry of the WORK array, and no error
                     message related to LWORK is issued by XERBLA.

           INFO

                     INFO is INTEGER
                     = 0:  successful exit
                     < 0:  if INFO = -i, the i-th argument has an illegal value

       Author
           Univ. of Tennessee

           Univ. of California Berkeley

           Univ. of Colorado Denver

           NAG Ltd.

   subroutine zungql (integer m, integer n, integer k, complex*16, dimension( lda, * ) a, integer
       lda, complex*16, dimension( * ) tau, complex*16, dimension( * ) work, integer lwork,
       integer info)
       ZUNGQL

       Purpose:

            ZUNGQL generates an M-by-N complex matrix Q with orthonormal columns,
            which is defined as the last N columns of a product of K elementary
            reflectors of order M

                  Q  =  H(k) . . . H(2) H(1)

            as returned by ZGEQLF.

       Parameters
           M

                     M is INTEGER
                     The number of rows of the matrix Q. M >= 0.

           N

                     N is INTEGER
                     The number of columns of the matrix Q. M >= N >= 0.

           K

                     K is INTEGER
                     The number of elementary reflectors whose product defines the
                     matrix Q. N >= K >= 0.

           A

                     A is COMPLEX*16 array, dimension (LDA,N)
                     On entry, the (n-k+i)-th column must contain the vector which
                     defines the elementary reflector H(i), for i = 1,2,...,k, as
                     returned by ZGEQLF in the last k columns of its array
                     argument A.
                     On exit, the M-by-N matrix Q.

           LDA

                     LDA is INTEGER
                     The first dimension of the array A. LDA >= max(1,M).

           TAU

                     TAU is COMPLEX*16 array, dimension (K)
                     TAU(i) must contain the scalar factor of the elementary
                     reflector H(i), as returned by ZGEQLF.

           WORK

                     WORK is COMPLEX*16 array, dimension (MAX(1,LWORK))
                     On exit, if INFO = 0, WORK(1) returns the optimal LWORK.

           LWORK

                     LWORK is INTEGER
                     The dimension of the array WORK. LWORK >= max(1,N).
                     For optimum performance LWORK >= N*NB, where NB is the
                     optimal blocksize.

                     If LWORK = -1, then a workspace query is assumed; the routine
                     only calculates the optimal size of the WORK array, returns
                     this value as the first entry of the WORK array, and no error
                     message related to LWORK is issued by XERBLA.

           INFO

                     INFO is INTEGER
                     = 0:  successful exit
                     < 0:  if INFO = -i, the i-th argument has an illegal value

       Author
           Univ. of Tennessee

           Univ. of California Berkeley

           Univ. of Colorado Denver

           NAG Ltd.

Author

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