From db464f35f5a10b58d9ed1085e0b462689adee583 Mon Sep 17 00:00:00 2001
From: Siddhesh Wani
Date: Mon, 25 May 2015 14:46:31 +0530
Subject: Original Version

---
 src/fortran/lapack/dormlq.f | 267 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 267 insertions(+)
 create mode 100644 src/fortran/lapack/dormlq.f

(limited to 'src/fortran/lapack/dormlq.f')

diff --git a/src/fortran/lapack/dormlq.f b/src/fortran/lapack/dormlq.f
new file mode 100644
index 0000000..f0c68ef
--- /dev/null
+++ b/src/fortran/lapack/dormlq.f
@@ -0,0 +1,267 @@
+      SUBROUTINE DORMLQ( SIDE, TRANS, M, N, K, A, LDA, TAU, C, LDC,
+     $                   WORK, LWORK, INFO )
+*
+*  -- LAPACK routine (version 3.1) --
+*     Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd..
+*     November 2006
+*
+*     .. Scalar Arguments ..
+      CHARACTER          SIDE, TRANS
+      INTEGER            INFO, K, LDA, LDC, LWORK, M, N
+*     ..
+*     .. Array Arguments ..
+      DOUBLE PRECISION   A( LDA, * ), C( LDC, * ), TAU( * ), WORK( * )
+*     ..
+*
+*  Purpose
+*  =======
+*
+*  DORMLQ 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 k
+*  elementary reflectors
+*
+*        Q = H(k) . . . H(2) H(1)
+*
+*  as returned by DGELQF. Q is of order M if SIDE = 'L' and of order N
+*  if SIDE = 'R'.
+*
+*  Arguments
+*  =========
+*
+*  SIDE    (input) CHARACTER*1
+*          = 'L': apply Q or Q**T from the Left;
+*          = 'R': apply Q or Q**T from the Right.
+*
+*  TRANS   (input) CHARACTER*1
+*          = 'N':  No transpose, apply Q;
+*          = 'T':  Transpose, apply Q**T.
+*
+*  M       (input) INTEGER
+*          The number of rows of the matrix C. M >= 0.
+*
+*  N       (input) INTEGER
+*          The number of columns of the matrix C. N >= 0.
+*
+*  K       (input) 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       (input) DOUBLE PRECISION array, dimension
+*                               (LDA,M) if SIDE = 'L',
+*                               (LDA,N) if SIDE = 'R'
+*          The i-th row must contain the vector which defines the
+*          elementary reflector H(i), for i = 1,2,...,k, as returned by
+*          DGELQF in the first k rows of its array argument A.
+*          A is modified by the routine but restored on exit.
+*
+*  LDA     (input) INTEGER
+*          The leading dimension of the array A. LDA >= max(1,K).
+*
+*  TAU     (input) DOUBLE PRECISION array, dimension (K)
+*          TAU(i) must contain the scalar factor of the elementary
+*          reflector H(i), as returned by DGELQF.
+*
+*  C       (input/output) 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     (input) INTEGER
+*          The leading dimension of the array C. LDC >= max(1,M).
+*
+*  WORK    (workspace/output) DOUBLE PRECISION array, dimension (MAX(1,LWORK))
+*          On exit, if INFO = 0, WORK(1) returns the optimal LWORK.
+*
+*  LWORK   (input) INTEGER
+*          The dimension of the array WORK.
+*          If SIDE = 'L', LWORK >= max(1,N);
+*          if SIDE = 'R', LWORK >= max(1,M).
+*          For optimum performance LWORK >= N*NB if SIDE = 'L', and
+*          LWORK >= M*NB if SIDE = 'R', 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    (output) INTEGER
+*          = 0:  successful exit
+*          < 0:  if INFO = -i, the i-th argument had an illegal value
+*
+*  =====================================================================
+*
+*     .. Parameters ..
+      INTEGER            NBMAX, LDT
+      PARAMETER          ( NBMAX = 64, LDT = NBMAX+1 )
+*     ..
+*     .. Local Scalars ..
+      LOGICAL            LEFT, LQUERY, NOTRAN
+      CHARACTER          TRANST
+      INTEGER            I, I1, I2, I3, IB, IC, IINFO, IWS, JC, LDWORK,
+     $                   LWKOPT, MI, NB, NBMIN, NI, NQ, NW
+*     ..
+*     .. Local Arrays ..
+      DOUBLE PRECISION   T( LDT, NBMAX )
+*     ..
+*     .. External Functions ..
+      LOGICAL            LSAME
+      INTEGER            ILAENV
+      EXTERNAL           LSAME, ILAENV
+*     ..
+*     .. External Subroutines ..
+      EXTERNAL           DLARFB, DLARFT, DORML2, XERBLA
+*     ..
+*     .. Intrinsic Functions ..
+      INTRINSIC          MAX, MIN
+*     ..
+*     .. Executable Statements ..
+*
+*     Test the input arguments
+*
+      INFO = 0
+      LEFT = LSAME( SIDE, 'L' )
+      NOTRAN = LSAME( TRANS, 'N' )
+      LQUERY = ( LWORK.EQ.-1 )
+*
+*     NQ is the order of Q and NW is the minimum dimension of WORK
+*
+      IF( LEFT ) THEN
+         NQ = M
+         NW = N
+      ELSE
+         NQ = N
+         NW = M
+      END IF
+      IF( .NOT.LEFT .AND. .NOT.LSAME( SIDE, 'R' ) ) THEN
+         INFO = -1
+      ELSE IF( .NOT.NOTRAN .AND. .NOT.LSAME( TRANS, 'T' ) ) THEN
+         INFO = -2
+      ELSE IF( M.LT.0 ) THEN
+         INFO = -3
+      ELSE IF( N.LT.0 ) THEN
+         INFO = -4
+      ELSE IF( K.LT.0 .OR. K.GT.NQ ) THEN
+         INFO = -5
+      ELSE IF( LDA.LT.MAX( 1, K ) ) THEN
+         INFO = -7
+      ELSE IF( LDC.LT.MAX( 1, M ) ) THEN
+         INFO = -10
+      ELSE IF( LWORK.LT.MAX( 1, NW ) .AND. .NOT.LQUERY ) THEN
+         INFO = -12
+      END IF
+*
+      IF( INFO.EQ.0 ) THEN
+*
+*        Determine the block size.  NB may be at most NBMAX, where NBMAX
+*        is used to define the local array T.
+*
+         NB = MIN( NBMAX, ILAENV( 1, 'DORMLQ', SIDE // TRANS, M, N, K,
+     $        -1 ) )
+         LWKOPT = MAX( 1, NW )*NB
+         WORK( 1 ) = LWKOPT
+      END IF
+*
+      IF( INFO.NE.0 ) THEN
+         CALL XERBLA( 'DORMLQ', -INFO )
+         RETURN
+      ELSE IF( LQUERY ) THEN
+         RETURN
+      END IF
+*
+*     Quick return if possible
+*
+      IF( M.EQ.0 .OR. N.EQ.0 .OR. K.EQ.0 ) THEN
+         WORK( 1 ) = 1
+         RETURN
+      END IF
+*
+      NBMIN = 2
+      LDWORK = NW
+      IF( NB.GT.1 .AND. NB.LT.K ) THEN
+         IWS = NW*NB
+         IF( LWORK.LT.IWS ) THEN
+            NB = LWORK / LDWORK
+            NBMIN = MAX( 2, ILAENV( 2, 'DORMLQ', SIDE // TRANS, M, N, K,
+     $              -1 ) )
+         END IF
+      ELSE
+         IWS = NW
+      END IF
+*
+      IF( NB.LT.NBMIN .OR. NB.GE.K ) THEN
+*
+*        Use unblocked code
+*
+         CALL DORML2( SIDE, TRANS, M, N, K, A, LDA, TAU, C, LDC, WORK,
+     $                IINFO )
+      ELSE
+*
+*        Use blocked code
+*
+         IF( ( LEFT .AND. NOTRAN ) .OR.
+     $       ( .NOT.LEFT .AND. .NOT.NOTRAN ) ) THEN
+            I1 = 1
+            I2 = K
+            I3 = NB
+         ELSE
+            I1 = ( ( K-1 ) / NB )*NB + 1
+            I2 = 1
+            I3 = -NB
+         END IF
+*
+         IF( LEFT ) THEN
+            NI = N
+            JC = 1
+         ELSE
+            MI = M
+            IC = 1
+         END IF
+*
+         IF( NOTRAN ) THEN
+            TRANST = 'T'
+         ELSE
+            TRANST = 'N'
+         END IF
+*
+         DO 10 I = I1, I2, I3
+            IB = MIN( NB, K-I+1 )
+*
+*           Form the triangular factor of the block reflector
+*           H = H(i) H(i+1) . . . H(i+ib-1)
+*
+            CALL DLARFT( 'Forward', 'Rowwise', NQ-I+1, IB, A( I, I ),
+     $                   LDA, TAU( I ), T, LDT )
+            IF( LEFT ) THEN
+*
+*              H or H' is applied to C(i:m,1:n)
+*
+               MI = M - I + 1
+               IC = I
+            ELSE
+*
+*              H or H' is applied to C(1:m,i:n)
+*
+               NI = N - I + 1
+               JC = I
+            END IF
+*
+*           Apply H or H'
+*
+            CALL DLARFB( SIDE, TRANST, 'Forward', 'Rowwise', MI, NI, IB,
+     $                   A( I, I ), LDA, T, LDT, C( IC, JC ), LDC, WORK,
+     $                   LDWORK )
+   10    CONTINUE
+      END IF
+      WORK( 1 ) = LWKOPT
+      RETURN
+*
+*     End of DORMLQ
+*
+      END
-- 
cgit