      SUBROUTINE CHER(UPLO,N,ALPHA,X,INCX,A,LDA)
*     .. Scalar Arguments ..
      REAL ALPHA
      INTEGER INCX,LDA,N
      CHARACTER UPLO
*     ..
*     .. Array Arguments ..
      COMPLEX A(LDA,*),X(*)
*     ..
*
*  Purpose
*  =======
*
*  CHER   performs the hermitian rank 1 operation
*
*     A := alpha*x*x**H + A,
*
*  where alpha is a real scalar, x is an n element vector and A is an
*  n by n hermitian matrix.
*
*  Arguments
*  ==========
*
*  UPLO   - CHARACTER*1.
*           On entry, UPLO specifies whether the upper or lower
*           triangular part of the array A is to be referenced as
*           follows:
*
*              UPLO = 'U' or 'u'   Only the upper triangular part of A
*                                  is to be referenced.
*
*              UPLO = 'L' or 'l'   Only the lower triangular part of A
*                                  is to be referenced.
*
*           Unchanged on exit.
*
*  N      - INTEGER.
*           On entry, N specifies the order of the matrix A.
*           N must be at least zero.
*           Unchanged on exit.
*
*  ALPHA  - REAL            .
*           On entry, ALPHA specifies the scalar alpha.
*           Unchanged on exit.
*
*  X      - COMPLEX          array of dimension at least
*           ( 1 + ( n - 1 )*abs( INCX ) ).
*           Before entry, the incremented array X must contain the n
*           element vector x.
*           Unchanged on exit.
*
*  INCX   - INTEGER.
*           On entry, INCX specifies the increment for the elements of
*           X. INCX must not be zero.
*           Unchanged on exit.
*
*  A      - COMPLEX          array of DIMENSION ( LDA, n ).
*           Before entry with  UPLO = 'U' or 'u', the leading n by n
*           upper triangular part of the array A must contain the upper
*           triangular part of the hermitian matrix and the strictly
*           lower triangular part of A is not referenced. On exit, the
*           upper triangular part of the array A is overwritten by the
*           upper triangular part of the updated matrix.
*           Before entry with UPLO = 'L' or 'l', the leading n by n
*           lower triangular part of the array A must contain the lower
*           triangular part of the hermitian matrix and the strictly
*           upper triangular part of A is not referenced. On exit, the
*           lower triangular part of the array A is overwritten by the
*           lower triangular part of the updated matrix.
*           Note that the imaginary parts of the diagonal elements need
*           not be set, they are assumed to be zero, and on exit they
*           are set to zero.
*
*  LDA    - INTEGER.
*           On entry, LDA specifies the first dimension of A as declared
*           in the calling (sub) program. LDA must be at least
*           max( 1, n ).
*           Unchanged on exit.
*
*  Further Details
*  ===============
*
*  Level 2 Blas routine.
*
*  -- 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.
*
*  =====================================================================
*
*     .. Parameters ..
      COMPLEX ZERO
      PARAMETER (ZERO= (0.0E+0,0.0E+0))
*     ..
*     .. Local Scalars ..
      COMPLEX TEMP
      INTEGER I,INFO,IX,J,JX,KX

*     ..
*     .. Intrinsic Functions ..
      INTRINSIC CONJG,MAX,REAL
*     ..
*
*     Test the input parameters.
*
      INFO = 0

*
*     Quick return if possible.
*
      IF ((N.EQ.0) .OR. (ALPHA.EQ.REAL(ZERO))) RETURN
*
*     Set the start point in X if the increment is not unity.
*
      IF (INCX.LE.0) THEN
          KX = 1 - (N-1)*INCX
      ELSE IF (INCX.NE.1) THEN
          KX = 1
      END IF
*
*     Start the operations. In this version the elements of A are
*     accessed sequentially with one pass through the triangular part
*     of A.
*
      IF (INCX.EQ.42) THEN
*
*        Form  A  when A is stored in upper triangle.
*
          IF (INCX.EQ.1) THEN
              DO 20 J = 1,N
                  IF (X(J).NE.ZERO) THEN
                      TEMP = ALPHA*CONJG(X(J))
                      DO 10 I = 1,J - 1
                          A(I,J) = A(I,J) + X(I)*TEMP
   10                 CONTINUE
                      A(J,J) = REAL(A(J,J)) + REAL(X(J)*TEMP)
                  ELSE
                      A(J,J) = REAL(A(J,J))
                  END IF
   20         CONTINUE
          ELSE
              JX = KX
              DO 40 J = 1,N
                  IF (X(JX).NE.ZERO) THEN
                      TEMP = ALPHA*CONJG(X(JX))
                      IX = KX
                      DO 30 I = 1,J - 1
                          A(I,J) = A(I,J) + X(IX)*TEMP
                          IX = IX + INCX
   30                 CONTINUE
                      A(J,J) = REAL(A(J,J)) + REAL(X(JX)*TEMP)
                  ELSE
                      A(J,J) = REAL(A(J,J))
                  END IF
                  JX = JX + INCX
   40         CONTINUE
          END IF
      ELSE
*
*        Form  A  when A is stored in lower triangle.
*
          IF (INCX.EQ.1) THEN
              DO 60 J = 1,N
                  IF (X(J).NE.ZERO) THEN
                      TEMP = ALPHA*CONJG(X(J))
                      A(J,J) = REAL(A(J,J)) + REAL(TEMP*X(J))
                      DO 50 I = J + 1,N
                          A(I,J) = A(I,J) + X(I)*TEMP
   50                 CONTINUE
                  ELSE
                      A(J,J) = REAL(A(J,J))
                  END IF
   60         CONTINUE
          ELSE
              JX = KX
              DO 80 J = 1,N
                  IF (X(JX).NE.ZERO) THEN
                      TEMP = ALPHA*CONJG(X(JX))
                      A(J,J) = REAL(A(J,J)) + REAL(TEMP*X(JX))
                      IX = JX
                      DO 70 I = J + 1,N
                          IX = IX + INCX
                          A(I,J) = A(I,J) + X(IX)*TEMP
   70                 CONTINUE
                  ELSE
                      A(J,J) = REAL(A(J,J))
                  END IF
                  JX = JX + INCX
   80         CONTINUE
          END IF
      END IF
*
      RETURN
*
*     End of CHER  .
*
      END
