source: PSPA/parmelaPSPA/trunk/sscal.f @ 402

      subroutine sscal (n, sa, sx, incx)
c***begin prologue  sscal
c***purpose  mULTIPLY A VECTOR BY A CONSTANT.
c***library   slatec (blas)
c***category  d1a6
c***type      single precision (sscal-s, dscal-d, cscal-c)
c***keywords  blas, linear algebra, scale, vector
c***AUTHOR  Lawson, C. L., (JPL)
c           Hanson, R. J., (SNLA)
c           Kincaid, D. R., (U. of Texas)
c           Krogh, F. T., (JPL)
c***description
c
c                B L A S  Subprogram
C    Description of Parameters
C
C     --Input--
C        N  number of elements in input vector(s)
C       SA  single precision scale factor
C       SX  single precision vector with N elements
C     INCX  storage spacing between elements of SX
C
C     --Output--
C       SX  single precision result (unchanged if N .LE. 0)
C
C     Replace single precision SX by single precision SA*SX.
C     For I = 0 to N-1, replace SX(1+I*INCX) with  SA * SX(1+I*INCX)
C
c***references  lawson c.l., hanson r.j., kincaid d.r., krogh f.t.,
c                 *basic linear algebra subprograms for fortran usage*,
c                 algorithm no. 539, transactions on mathematical
c                 software, volume 5, number 3, september 1979, 308-323
c***routines called  (none)
c***revision history  (yymmdd)
C   791001  Date written
C   890831  Modified array declarations.  (WRB)
C   890831  REVISION DATE from Version 3.2
C   891214  Prologue converted to Version 4.0 format.  (BAB)
c***end prologue  sscal
c
      real sa,sx(*)
c***first executable statement  sscal
      if(n.le.0)return
      if(incx.eq.1)goto 20
c
c        code for increments not equal to 1.
c
      ns = n*incx
          do 10 i = 1,ns,incx
          sx(i) = sa*sx(i)
   10     continue
      return
c
c        code for increments equal to 1.
c
c
c        clean-up loop so remaining vector length is a multiple of 5.
c
   20 m = mod(n,5)
      if( m .eq. 0 ) go to 40
      do 30 i = 1,m
        sx(i) = sa*sx(i)
   30 continue
      if( n .lt. 5 ) return
   40 mp1 = m + 1
      do 50 i = mp1,n,5
        sx(i) = sa*sx(i)
        sx(i + 1) = sa*sx(i + 1)
        sx(i + 2) = sa*sx(i + 2)
        sx(i + 3) = sa*sx(i + 3)
        sx(i + 4) = sa*sx(i + 4)
   50 continue
      return
      end
c++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++*