--- /dev/null
+*> \brief \b DGEMV
+*
+* =========== DOCUMENTATION ===========
+*
+* Online html documentation available at
+* http://www.netlib.org/lapack/explore-html/
+*
+* Definition:
+* ===========
+*
+* SUBROUTINE DGEMV(TRANS,M,N,ALPHA,A,LDA,X,INCX,BETA,Y,INCY)
+*
+* .. Scalar Arguments ..
+* DOUBLE PRECISION ALPHA,BETA
+* INTEGER INCX,INCY,LDA,M,N
+* CHARACTER TRANS
+* ..
+* .. Array Arguments ..
+* DOUBLE PRECISION A(LDA,*),X(*),Y(*)
+* ..
+*
+*
+*> \par Purpose:
+* =============
+*>
+*> \verbatim
+*>
+*> DGEMV performs one of the matrix-vector operations
+*>
+*> y := alpha*A*x + beta*y, or y := alpha*A**T*x + beta*y,
+*>
+*> where alpha and beta are scalars, x and y are vectors and A is an
+*> m by n matrix.
+*> \endverbatim
+*
+* Arguments:
+* ==========
+*
+*> \param[in] TRANS
+*> \verbatim
+*> TRANS is CHARACTER*1
+*> On entry, TRANS specifies the operation to be performed as
+*> follows:
+*>
+*> TRANS = 'N' or 'n' y := alpha*A*x + beta*y.
+*>
+*> TRANS = 'T' or 't' y := alpha*A**T*x + beta*y.
+*>
+*> TRANS = 'C' or 'c' y := alpha*A**T*x + beta*y.
+*> \endverbatim
+*>
+*> \param[in] M
+*> \verbatim
+*> M is INTEGER
+*> On entry, M specifies the number of rows of the matrix A.
+*> M must be at least zero.
+*> \endverbatim
+*>
+*> \param[in] N
+*> \verbatim
+*> N is INTEGER
+*> On entry, N specifies the number of columns of the matrix A.
+*> N must be at least zero.
+*> \endverbatim
+*>
+*> \param[in] ALPHA
+*> \verbatim
+*> ALPHA is DOUBLE PRECISION.
+*> On entry, ALPHA specifies the scalar alpha.
+*> \endverbatim
+*>
+*> \param[in] A
+*> \verbatim
+*> A is DOUBLE PRECISION array of DIMENSION ( LDA, n ).
+*> Before entry, the leading m by n part of the array A must
+*> contain the matrix of coefficients.
+*> \endverbatim
+*>
+*> \param[in] LDA
+*> \verbatim
+*> LDA is INTEGER
+*> On entry, LDA specifies the first dimension of A as declared
+*> in the calling (sub) program. LDA must be at least
+*> max( 1, m ).
+*> \endverbatim
+*>
+*> \param[in] X
+*> \verbatim
+*> X is DOUBLE PRECISION array of DIMENSION at least
+*> ( 1 + ( n - 1 )*abs( INCX ) ) when TRANS = 'N' or 'n'
+*> and at least
+*> ( 1 + ( m - 1 )*abs( INCX ) ) otherwise.
+*> Before entry, the incremented array X must contain the
+*> vector x.
+*> \endverbatim
+*>
+*> \param[in] INCX
+*> \verbatim
+*> INCX is INTEGER
+*> On entry, INCX specifies the increment for the elements of
+*> X. INCX must not be zero.
+*> \endverbatim
+*>
+*> \param[in] BETA
+*> \verbatim
+*> BETA is DOUBLE PRECISION.
+*> On entry, BETA specifies the scalar beta. When BETA is
+*> supplied as zero then Y need not be set on input.
+*> \endverbatim
+*>
+*> \param[in,out] Y
+*> \verbatim
+*> Y is DOUBLE PRECISION array of DIMENSION at least
+*> ( 1 + ( m - 1 )*abs( INCY ) ) when TRANS = 'N' or 'n'
+*> and at least
+*> ( 1 + ( n - 1 )*abs( INCY ) ) otherwise.
+*> Before entry with BETA non-zero, the incremented array Y
+*> must contain the vector y. On exit, Y is overwritten by the
+*> updated vector y.
+*> \endverbatim
+*>
+*> \param[in] INCY
+*> \verbatim
+*> INCY is INTEGER
+*> On entry, INCY specifies the increment for the elements of
+*> Y. INCY must not be zero.
+*> \endverbatim
+*
+* Authors:
+* ========
+*
+*> \author Univ. of Tennessee
+*> \author Univ. of California Berkeley
+*> \author Univ. of Colorado Denver
+*> \author NAG Ltd.
+*
+*> \date November 2015
+*
+*> \ingroup double_blas_level2
+*
+*> \par Further Details:
+* =====================
+*>
+*> \verbatim
+*>
+*> Level 2 Blas routine.
+*> The vector and matrix arguments are not referenced when N = 0, or M = 0
+*>
+*> -- Written on 22-October-1986.
+*> Jack Dongarra, Argonne National Lab.
+*> Jeremy Du Croz, Nag Central Office.
+*> Sven Hammarling, Nag Central Office.
+*> Richard Hanson, Sandia National Labs.
+*> \endverbatim
+*>
+* =====================================================================
+ SUBROUTINE DGEMV(TRANS,M,N,ALPHA,A,LDA,X,INCX,BETA,Y,INCY)
+*
+* -- Reference BLAS level2 routine (version 3.6.0) --
+* -- Reference BLAS is a software package provided by Univ. of Tennessee, --
+* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
+* November 2015
+*
+* .. Scalar Arguments ..
+ DOUBLE PRECISION ALPHA,BETA
+ INTEGER INCX,INCY,LDA,M,N
+ CHARACTER TRANS
+* ..
+* .. Array Arguments ..
+ DOUBLE PRECISION A(LDA,*),X(*),Y(*)
+* ..
+*
+* =====================================================================
+*
+* .. Parameters ..
+ DOUBLE PRECISION ONE,ZERO
+ PARAMETER (ONE=1.0D+0,ZERO=0.0D+0)
+* ..
+* .. Local Scalars ..
+ DOUBLE PRECISION TEMP
+ INTEGER I,INFO,IX,IY,J,JX,JY,KX,KY,LENX,LENY
+* ..
+* .. External Functions ..
+ LOGICAL LSAME
+ EXTERNAL LSAME
+* ..
+* .. External Subroutines ..
+ EXTERNAL XERBLA
+* ..
+* .. Intrinsic Functions ..
+ INTRINSIC MAX
+* ..
+*
+* Test the input parameters.
+*
+ INFO = 0
+ IF (.NOT.LSAME(TRANS,'N') .AND. .NOT.LSAME(TRANS,'T') .AND.
+ + .NOT.LSAME(TRANS,'C')) THEN
+ INFO = 1
+ ELSE IF (M.LT.0) THEN
+ INFO = 2
+ ELSE IF (N.LT.0) THEN
+ INFO = 3
+ ELSE IF (LDA.LT.MAX(1,M)) THEN
+ INFO = 6
+ ELSE IF (INCX.EQ.0) THEN
+ INFO = 8
+ ELSE IF (INCY.EQ.0) THEN
+ INFO = 11
+ END IF
+ IF (INFO.NE.0) THEN
+ CALL XERBLA('DGEMV ',INFO)
+ RETURN
+ END IF
+*
+* Quick return if possible.
+*
+ IF ((M.EQ.0) .OR. (N.EQ.0) .OR.
+ + ((ALPHA.EQ.ZERO).AND. (BETA.EQ.ONE))) RETURN
+*
+* Set LENX and LENY, the lengths of the vectors x and y, and set
+* up the start points in X and Y.
+*
+ IF (LSAME(TRANS,'N')) THEN
+ LENX = N
+ LENY = M
+ ELSE
+ LENX = M
+ LENY = N
+ END IF
+ IF (INCX.GT.0) THEN
+ KX = 1
+ ELSE
+ KX = 1 - (LENX-1)*INCX
+ END IF
+ IF (INCY.GT.0) THEN
+ KY = 1
+ ELSE
+ KY = 1 - (LENY-1)*INCY
+ END IF
+*
+* Start the operations. In this version the elements of A are
+* accessed sequentially with one pass through A.
+*
+* First form y := beta*y.
+*
+ IF (BETA.NE.ONE) THEN
+ IF (INCY.EQ.1) THEN
+ IF (BETA.EQ.ZERO) THEN
+ DO 10 I = 1,LENY
+ Y(I) = ZERO
+ 10 CONTINUE
+ ELSE
+ DO 20 I = 1,LENY
+ Y(I) = BETA*Y(I)
+ 20 CONTINUE
+ END IF
+ ELSE
+ IY = KY
+ IF (BETA.EQ.ZERO) THEN
+ DO 30 I = 1,LENY
+ Y(IY) = ZERO
+ IY = IY + INCY
+ 30 CONTINUE
+ ELSE
+ DO 40 I = 1,LENY
+ Y(IY) = BETA*Y(IY)
+ IY = IY + INCY
+ 40 CONTINUE
+ END IF
+ END IF
+ END IF
+ IF (ALPHA.EQ.ZERO) RETURN
+ IF (LSAME(TRANS,'N')) THEN
+*
+* Form y := alpha*A*x + y.
+*
+ JX = KX
+ IF (INCY.EQ.1) THEN
+ DO 60 J = 1,N
+ TEMP = ALPHA*X(JX)
+ DO 50 I = 1,M
+ Y(I) = Y(I) + TEMP*A(I,J)
+ 50 CONTINUE
+ JX = JX + INCX
+ 60 CONTINUE
+ ELSE
+ DO 80 J = 1,N
+ TEMP = ALPHA*X(JX)
+ IY = KY
+ DO 70 I = 1,M
+ Y(IY) = Y(IY) + TEMP*A(I,J)
+ IY = IY + INCY
+ 70 CONTINUE
+ JX = JX + INCX
+ 80 CONTINUE
+ END IF
+ ELSE
+*
+* Form y := alpha*A**T*x + y.
+*
+ JY = KY
+ IF (INCX.EQ.1) THEN
+ DO 100 J = 1,N
+ TEMP = ZERO
+ DO 90 I = 1,M
+ TEMP = TEMP + A(I,J)*X(I)
+ 90 CONTINUE
+ Y(JY) = Y(JY) + ALPHA*TEMP
+ JY = JY + INCY
+ 100 CONTINUE
+ ELSE
+ DO 120 J = 1,N
+ TEMP = ZERO
+ IX = KX
+ DO 110 I = 1,M
+ TEMP = TEMP + A(I,J)*X(IX)
+ IX = IX + INCX
+ 110 CONTINUE
+ Y(JY) = Y(JY) + ALPHA*TEMP
+ JY = JY + INCY
+ 120 CONTINUE
+ END IF
+ END IF
+*
+ RETURN
+*
+* End of DGEMV .
+*
+ END
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