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SUBROUTINE <a name="SSYMV.1"></a><a href="ssymv.f.html#SSYMV.1">SSYMV</a>(UPLO,N,ALPHA,A,LDA,X,INCX,BETA,Y,INCY)
<span class="comment">*</span><span class="comment"> .. Scalar Arguments ..
</span> REAL ALPHA,BETA
INTEGER INCX,INCY,LDA,N
CHARACTER UPLO
<span class="comment">*</span><span class="comment"> ..
</span><span class="comment">*</span><span class="comment"> .. Array Arguments ..
</span> REAL A(LDA,*),X(*),Y(*)
<span class="comment">*</span><span class="comment"> ..
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> Purpose
</span><span class="comment">*</span><span class="comment"> =======
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> <a name="SSYMV.14"></a><a href="ssymv.f.html#SSYMV.1">SSYMV</a> performs the matrix-vector operation
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> y := alpha*A*x + beta*y,
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> where alpha and beta are scalars, x and y are n element vectors and
</span><span class="comment">*</span><span class="comment"> A is an n by n symmetric matrix.
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> Arguments
</span><span class="comment">*</span><span class="comment"> ==========
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> UPLO - CHARACTER*1.
</span><span class="comment">*</span><span class="comment"> On entry, UPLO specifies whether the upper or lower
</span><span class="comment">*</span><span class="comment"> triangular part of the array A is to be referenced as
</span><span class="comment">*</span><span class="comment"> follows:
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> UPLO = 'U' or 'u' Only the upper triangular part of A
</span><span class="comment">*</span><span class="comment"> is to be referenced.
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> UPLO = 'L' or 'l' Only the lower triangular part of A
</span><span class="comment">*</span><span class="comment"> is to be referenced.
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> Unchanged on exit.
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> N - INTEGER.
</span><span class="comment">*</span><span class="comment"> On entry, N specifies the order of the matrix A.
</span><span class="comment">*</span><span class="comment"> N must be at least zero.
</span><span class="comment">*</span><span class="comment"> Unchanged on exit.
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> ALPHA - REAL .
</span><span class="comment">*</span><span class="comment"> On entry, ALPHA specifies the scalar alpha.
</span><span class="comment">*</span><span class="comment"> Unchanged on exit.
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> A - REAL array of DIMENSION ( LDA, n ).
</span><span class="comment">*</span><span class="comment"> Before entry with UPLO = 'U' or 'u', the leading n by n
</span><span class="comment">*</span><span class="comment"> upper triangular part of the array A must contain the upper
</span><span class="comment">*</span><span class="comment"> triangular part of the symmetric matrix and the strictly
</span><span class="comment">*</span><span class="comment"> lower triangular part of A is not referenced.
</span><span class="comment">*</span><span class="comment"> Before entry with UPLO = 'L' or 'l', the leading n by n
</span><span class="comment">*</span><span class="comment"> lower triangular part of the array A must contain the lower
</span><span class="comment">*</span><span class="comment"> triangular part of the symmetric matrix and the strictly
</span><span class="comment">*</span><span class="comment"> upper triangular part of A is not referenced.
</span><span class="comment">*</span><span class="comment"> Unchanged on exit.
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> LDA - INTEGER.
</span><span class="comment">*</span><span class="comment"> On entry, LDA specifies the first dimension of A as declared
</span><span class="comment">*</span><span class="comment"> in the calling (sub) program. LDA must be at least
</span><span class="comment">*</span><span class="comment"> max( 1, n ).
</span><span class="comment">*</span><span class="comment"> Unchanged on exit.
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> X - REAL array of dimension at least
</span><span class="comment">*</span><span class="comment"> ( 1 + ( n - 1 )*abs( INCX ) ).
</span><span class="comment">*</span><span class="comment"> Before entry, the incremented array X must contain the n
</span><span class="comment">*</span><span class="comment"> element vector x.
</span><span class="comment">*</span><span class="comment"> Unchanged on exit.
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> INCX - INTEGER.
</span><span class="comment">*</span><span class="comment"> On entry, INCX specifies the increment for the elements of
</span><span class="comment">*</span><span class="comment"> X. INCX must not be zero.
</span><span class="comment">*</span><span class="comment"> Unchanged on exit.
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> BETA - REAL .
</span><span class="comment">*</span><span class="comment"> On entry, BETA specifies the scalar beta. When BETA is
</span><span class="comment">*</span><span class="comment"> supplied as zero then Y need not be set on input.
</span><span class="comment">*</span><span class="comment"> Unchanged on exit.
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> Y - REAL array of dimension at least
</span><span class="comment">*</span><span class="comment"> ( 1 + ( n - 1 )*abs( INCY ) ).
</span><span class="comment">*</span><span class="comment"> Before entry, the incremented array Y must contain the n
</span><span class="comment">*</span><span class="comment"> element vector y. On exit, Y is overwritten by the updated
</span><span class="comment">*</span><span class="comment"> vector y.
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> INCY - INTEGER.
</span><span class="comment">*</span><span class="comment"> On entry, INCY specifies the increment for the elements of
</span><span class="comment">*</span><span class="comment"> Y. INCY must not be zero.
</span><span class="comment">*</span><span class="comment"> Unchanged on exit.
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> Level 2 Blas routine.
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> -- Written on 22-October-1986.
</span><span class="comment">*</span><span class="comment"> Jack Dongarra, Argonne National Lab.
</span><span class="comment">*</span><span class="comment"> Jeremy Du Croz, Nag Central Office.
</span><span class="comment">*</span><span class="comment"> Sven Hammarling, Nag Central Office.
</span><span class="comment">*</span><span class="comment"> Richard Hanson, Sandia National Labs.
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> .. Parameters ..
</span> REAL ONE,ZERO
PARAMETER (ONE=1.0E+0,ZERO=0.0E+0)
<span class="comment">*</span><span class="comment"> ..
</span><span class="comment">*</span><span class="comment"> .. Local Scalars ..
</span> REAL TEMP1,TEMP2
INTEGER I,INFO,IX,IY,J,JX,JY,KX,KY
<span class="comment">*</span><span class="comment"> ..
</span><span class="comment">*</span><span class="comment"> .. External Functions ..
</span> LOGICAL <a name="LSAME.109"></a><a href="lsame.f.html#LSAME.1">LSAME</a>
EXTERNAL <a name="LSAME.110"></a><a href="lsame.f.html#LSAME.1">LSAME</a>
<span class="comment">*</span><span class="comment"> ..
</span><span class="comment">*</span><span class="comment"> .. External Subroutines ..
</span> EXTERNAL <a name="XERBLA.113"></a><a href="xerbla.f.html#XERBLA.1">XERBLA</a>
<span class="comment">*</span><span class="comment"> ..
</span><span class="comment">*</span><span class="comment"> .. Intrinsic Functions ..
</span> INTRINSIC MAX
<span class="comment">*</span><span class="comment"> ..
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> Test the input parameters.
</span><span class="comment">*</span><span class="comment">
</span> INFO = 0
IF (.NOT.<a name="LSAME.122"></a><a href="lsame.f.html#LSAME.1">LSAME</a>(UPLO,<span class="string">'U'</span>) .AND. .NOT.<a name="LSAME.122"></a><a href="lsame.f.html#LSAME.1">LSAME</a>(UPLO,<span class="string">'L'</span>)) THEN
INFO = 1
ELSE IF (N.LT.0) THEN
INFO = 2
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