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

NAME

       gemqr - gemqr: multiply by Q from geqr

SYNOPSIS

   Functions
       subroutine cgemqr (side, trans, m, n, k, a, lda, t, tsize, c, ldc, work, lwork, info)
           CGEMQR
       subroutine dgemqr (side, trans, m, n, k, a, lda, t, tsize, c, ldc, work, lwork, info)
           DGEMQR
       subroutine sgemqr (side, trans, m, n, k, a, lda, t, tsize, c, ldc, work, lwork, info)
           SGEMQR
       subroutine zgemqr (side, trans, m, n, k, a, lda, t, tsize, c, ldc, work, lwork, info)
           ZGEMQR

Detailed Description

Function Documentation

   subroutine cgemqr (character side, character trans, integer m, integer n, integer k, complex,
       dimension( lda, * ) a, integer lda, complex, dimension( * ) t, integer tsize, complex,
       dimension( ldc, * ) c, integer ldc, complex, dimension( * ) work, integer lwork, integer
       info)
       CGEMQR

       Purpose:

            CGEMQR overwrites the general real M-by-N matrix C with

                                 SIDE = 'L'     SIDE = 'R'
                 TRANS = 'N':      Q * C          C * Q
                 TRANS = 'T':      Q**H * C       C * Q**H

            where Q is a complex unitary matrix defined as the product
            of blocked elementary reflectors computed by tall skinny
            QR factorization (CGEQR)

       Parameters
           SIDE

                     SIDE is CHARACTER*1
                     = 'L': apply Q or Q**H from the Left;
                     = 'R': apply Q or Q**H from the Right.

           TRANS

                     TRANS is CHARACTER*1
                     = 'N':  No transpose, apply Q;
                     = 'C':  Conjugate transpose, apply Q**H.

           M

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

           N

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

           K

                     K is INTEGER
                     The number of elementary reflectors whose product defines
                     the matrix Q.
                     If SIDE = 'L', M >= K >= 0;
                     if SIDE = 'R', N >= K >= 0.

           A

                     A is COMPLEX array, dimension (LDA,K)
                     Part of the data structure to represent Q as returned by CGEQR.

           LDA

                     LDA is INTEGER
                     The leading dimension of the array A.
                     If SIDE = 'L', LDA >= max(1,M);
                     if SIDE = 'R', LDA >= max(1,N).

           T

                     T is COMPLEX array, dimension (MAX(5,TSIZE)).
                     Part of the data structure to represent Q as returned by CGEQR.

           TSIZE

                     TSIZE is INTEGER
                     The dimension of the array T. TSIZE >= 5.

           C

                     C is COMPLEX array, dimension (LDC,N)
                     On entry, the M-by-N matrix C.
                     On exit, C is overwritten by Q*C or Q**H*C or C*Q**H or C*Q.

           LDC

                     LDC is INTEGER
                     The leading dimension of the array C. LDC >= max(1,M).

           WORK

                    (workspace) COMPLEX array, dimension (MAX(1,LWORK))

           LWORK

                     LWORK is INTEGER
                     The dimension of the array WORK.
                     If LWORK = -1, then a workspace query is assumed. The routine
                     only calculates the size of the WORK array, returns this
                     value as WORK(1), and no error message related to WORK
                     is issued by XERBLA.

           INFO

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

       Author
           Univ. of Tennessee

           Univ. of California Berkeley

           Univ. of Colorado Denver

           NAG Ltd.

       Further Details

            These details are particular for this LAPACK implementation. Users should not
            take them for granted. These details may change in the future, and are not likely
            true for another LAPACK implementation. These details are relevant if one wants
            to try to understand the code. They are not part of the interface.

            In this version,

                     T(2): row block size (MB)
                     T(3): column block size (NB)
                     T(6:TSIZE): data structure needed for Q, computed by
                                      CLATSQR or CGEQRT

             Depending on the matrix dimensions M and N, and row and column
             block sizes MB and NB returned by ILAENV, CGEQR will use either
             CLATSQR (if the matrix is tall-and-skinny) or CGEQRT to compute
             the QR factorization.
             This version of CGEMQR will use either CLAMTSQR or CGEMQRT to
             multiply matrix Q by another matrix.
             Further Details in CLAMTSQR or CGEMQRT.

   subroutine dgemqr (character side, character trans, integer m, integer n, integer k, double
       precision, dimension( lda, * ) a, integer lda, double precision, dimension( * ) t, integer
       tsize, double precision, dimension( ldc, * ) c, integer ldc, double precision, dimension(
       * ) work, integer lwork, integer info)
       DGEMQR

       Purpose:

            DGEMQR overwrites the general real M-by-N matrix C with

                                 SIDE = 'L'     SIDE = 'R'
                 TRANS = 'N':      Q * C          C * Q
                 TRANS = 'T':      Q**T * C       C * Q**T

            where Q is a real orthogonal matrix defined as the product
            of blocked elementary reflectors computed by tall skinny
            QR factorization (DGEQR)

       Parameters
           SIDE

                     SIDE is CHARACTER*1
                     = 'L': apply Q or Q**T from the Left;
                     = 'R': apply Q or Q**T from the Right.

           TRANS

                     TRANS is CHARACTER*1
                     = 'N':  No transpose, apply Q;
                     = 'T':  Transpose, apply Q**T.

           M

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

           N

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

           K

                     K is INTEGER
                     The number of elementary reflectors whose product defines
                     the matrix Q.
                     If SIDE = 'L', M >= K >= 0;
                     if SIDE = 'R', N >= K >= 0.

           A

                     A is DOUBLE PRECISION array, dimension (LDA,K)
                     Part of the data structure to represent Q as returned by DGEQR.

           LDA

                     LDA is INTEGER
                     The leading dimension of the array A.
                     If SIDE = 'L', LDA >= max(1,M);
                     if SIDE = 'R', LDA >= max(1,N).

           T

                     T is DOUBLE PRECISION array, dimension (MAX(5,TSIZE)).
                     Part of the data structure to represent Q as returned by DGEQR.

           TSIZE

                     TSIZE is INTEGER
                     The dimension of the array T. TSIZE >= 5.

           C

                     C is DOUBLE PRECISION array, dimension (LDC,N)
                     On entry, the M-by-N matrix C.
                     On exit, C is overwritten by Q*C or Q**T*C or C*Q**T or C*Q.

           LDC

                     LDC is INTEGER
                     The leading dimension of the array C. LDC >= max(1,M).

           WORK

                    (workspace) DOUBLE PRECISION array, dimension (MAX(1,LWORK))

           LWORK

                     LWORK is INTEGER
                     The dimension of the array WORK.
                     If LWORK = -1, then a workspace query is assumed. The routine
                     only calculates the size of the WORK array, returns this
                     value as WORK(1), and no error message related to WORK
                     is issued by XERBLA.

           INFO

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

       Author
           Univ. of Tennessee

           Univ. of California Berkeley

           Univ. of Colorado Denver

           NAG Ltd.

       Further Details

            These details are particular for this LAPACK implementation. Users should not
            take them for granted. These details may change in the future, and are not likely
            true for another LAPACK implementation. These details are relevant if one wants
            to try to understand the code. They are not part of the interface.

            In this version,

                     T(2): row block size (MB)
                     T(3): column block size (NB)
                     T(6:TSIZE): data structure needed for Q, computed by
                                      DLATSQR or DGEQRT

             Depending on the matrix dimensions M and N, and row and column
             block sizes MB and NB returned by ILAENV, DGEQR will use either
             DLATSQR (if the matrix is tall-and-skinny) or DGEQRT to compute
             the QR factorization.
             This version of DGEMQR will use either DLAMTSQR or DGEMQRT to
             multiply matrix Q by another matrix.
             Further Details in DLATMSQR or DGEMQRT.

   subroutine sgemqr (character side, character trans, integer m, integer n, integer k, real,
       dimension( lda, * ) a, integer lda, real, dimension( * ) t, integer tsize, real,
       dimension( ldc, * ) c, integer ldc, real, dimension( * ) work, integer lwork, integer
       info)
       SGEMQR

       Purpose:

            SGEMQR overwrites the general real M-by-N matrix C with

                                 SIDE = 'L'     SIDE = 'R'
                TRANS = 'N':      Q * C          C * Q
                TRANS = 'T':      Q**T * C       C * Q**T

            where Q is a real orthogonal matrix defined as the product
            of blocked elementary reflectors computed by tall skinny
            QR factorization (SGEQR)

       Parameters
           SIDE

                     SIDE is CHARACTER*1
                     = 'L': apply Q or Q**T from the Left;
                     = 'R': apply Q or Q**T from the Right.

           TRANS

                     TRANS is CHARACTER*1
                     = 'N':  No transpose, apply Q;
                     = 'T':  Transpose, apply Q**T.

           M

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

           N

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

           K

                     K is INTEGER
                     The number of elementary reflectors whose product defines
                     the matrix Q.
                     If SIDE = 'L', M >= K >= 0;
                     if SIDE = 'R', N >= K >= 0.

           A

                     A is REAL array, dimension (LDA,K)
                     Part of the data structure to represent Q as returned by SGEQR.

           LDA

                     LDA is INTEGER
                     The leading dimension of the array A.
                     If SIDE = 'L', LDA >= max(1,M);
                     if SIDE = 'R', LDA >= max(1,N).

           T

                     T is REAL array, dimension (MAX(5,TSIZE)).
                     Part of the data structure to represent Q as returned by SGEQR.

           TSIZE

                     TSIZE is INTEGER
                     The dimension of the array T. TSIZE >= 5.

           C

                     C is REAL array, dimension (LDC,N)
                     On entry, the M-by-N matrix C.
                     On exit, C is overwritten by Q*C or Q**T*C or C*Q**T or C*Q.

           LDC

                     LDC is INTEGER
                     The leading dimension of the array C. LDC >= max(1,M).

           WORK

                    (workspace) REAL array, dimension (MAX(1,LWORK))

           LWORK

                     LWORK is INTEGER
                     The dimension of the array WORK.
                     If LWORK = -1, then a workspace query is assumed. The routine
                     only calculates the size of the WORK array, returns this
                     value as WORK(1), and no error message related to WORK
                     is issued by XERBLA.

           INFO

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

       Author
           Univ. of Tennessee

           Univ. of California Berkeley

           Univ. of Colorado Denver

           NAG Ltd.

       Further Details

            These details are particular for this LAPACK implementation. Users should not
            take them for granted. These details may change in the future, and are not likely
            true for another LAPACK implementation. These details are relevant if one wants
            to try to understand the code. They are not part of the interface.

            In this version,

                     T(2): row block size (MB)
                     T(3): column block size (NB)
                     T(6:TSIZE): data structure needed for Q, computed by
                                      SLATSQR or SGEQRT

             Depending on the matrix dimensions M and N, and row and column
             block sizes MB and NB returned by ILAENV, SGEQR will use either
             SLATSQR (if the matrix is tall-and-skinny) or SGEQRT to compute
             the QR factorization.
             This version of SGEMQR will use either SLAMTSQR or SGEMQRT to
             multiply matrix Q by another matrix.
             Further Details in SLAMTSQR or SGEMQRT.

   subroutine zgemqr (character side, character trans, integer m, integer n, integer k,
       complex*16, dimension( lda, * ) a, integer lda, complex*16, dimension( * ) t, integer
       tsize, complex*16, dimension( ldc, * ) c, integer ldc, complex*16, dimension( * ) work,
       integer lwork, integer info)
       ZGEMQR

       Purpose:

            ZGEMQR overwrites the general real M-by-N matrix C with

                                 SIDE = 'L'     SIDE = 'R'
                 TRANS = 'N':      Q * C          C * Q
                 TRANS = 'T':      Q**H * C       C * Q**H

            where Q is a complex unitary matrix defined as the product
            of blocked elementary reflectors computed by tall skinny
            QR factorization (ZGEQR)

       Parameters
           SIDE

                     SIDE is CHARACTER*1
                     = 'L': apply Q or Q**H from the Left;
                     = 'R': apply Q or Q**H from the Right.

           TRANS

                     TRANS is CHARACTER*1
                     = 'N':  No transpose, apply Q;
                     = 'C':  Conjugate transpose, apply Q**H.

           M

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

           N

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

           K

                     K is INTEGER
                     The number of elementary reflectors whose product defines
                     the matrix Q.
                     If SIDE = 'L', M >= K >= 0;
                     if SIDE = 'R', N >= K >= 0.

           A

                     A is COMPLEX*16 array, dimension (LDA,K)
                     Part of the data structure to represent Q as returned by ZGEQR.

           LDA

                     LDA is INTEGER
                     The leading dimension of the array A.
                     If SIDE = 'L', LDA >= max(1,M);
                     if SIDE = 'R', LDA >= max(1,N).

           T

                     T is COMPLEX*16 array, dimension (MAX(5,TSIZE)).
                     Part of the data structure to represent Q as returned by ZGEQR.

           TSIZE

                     TSIZE is INTEGER
                     The dimension of the array T. TSIZE >= 5.

           C

                     C is COMPLEX*16 array, dimension (LDC,N)
                     On entry, the M-by-N matrix C.
                     On exit, C is overwritten by Q*C or Q**H*C or C*Q**H or C*Q.

           LDC

                     LDC is INTEGER
                     The leading dimension of the array C. LDC >= max(1,M).

           WORK

                    (workspace) COMPLEX*16 array, dimension (MAX(1,LWORK))

           LWORK

                     LWORK is INTEGER
                     The dimension of the array WORK.
                     If LWORK = -1, then a workspace query is assumed. The routine
                     only calculates the size of the WORK array, returns this
                     value as WORK(1), and no error message related to WORK
                     is issued by XERBLA.

           INFO

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

       Author
           Univ. of Tennessee

           Univ. of California Berkeley

           Univ. of Colorado Denver

           NAG Ltd.

       Further Details

            These details are particular for this LAPACK implementation. Users should not
            take them for granted. These details may change in the future, and are not likely
            true for another LAPACK implementation. These details are relevant if one wants
            to try to understand the code. They are not part of the interface.

            In this version,

                     T(2): row block size (MB)
                     T(3): column block size (NB)
                     T(6:TSIZE): data structure needed for Q, computed by
                                      ZLATSQR or ZGEQRT

             Depending on the matrix dimensions M and N, and row and column
             block sizes MB and NB returned by ILAENV, ZGEQR will use either
             ZLATSQR (if the matrix is tall-and-skinny) or ZGEQRT to compute
             the QR factorization.
             This version of ZGEMQR will use either ZLAMTSQR or ZGEMQRT to
             multiply matrix Q by another matrix.
             Further Details in ZLAMTSQR or ZGEMQRT.

Author

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