Note: this is a BLAS routine and is not in libslatec.a
*DECK SROTM
SUBROUTINE SROTM (N, SX, INCX, SY, INCY, SPARAM)
C***BEGIN PROLOGUE SROTM
C***PURPOSE Apply a modified Givens transformation.
C***LIBRARY SLATEC (BLAS)
C***CATEGORY D1A8
C***TYPE SINGLE PRECISION (SROTM-S, DROTM-D)
C***KEYWORDS BLAS, LINEAR ALGEBRA, MODIFIED GIVENS ROTATION, 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 SX single precision vector with N elements
C INCX storage spacing between elements of SX
C SY single precision vector with N elements
C INCY storage spacing between elements of SY
C SPARAM 5-element vector. SPARAM(1) is SFLAG described below.
C Locations 2-5 of SPARAM contain elements of the
C transformation matrix H described below.
C
C --Output--
C SX rotated vector (unchanged if N .LE. 0)
C SY rotated vector (unchanged if N .LE. 0)
C
C Apply the modified Givens transformation, H, to the 2 by N matrix
C (SX**T)
C (SY**T) , where **T indicates transpose. The elements of SX are
C in SX(LX+I*INCX), I = 0 to N-1, where LX = 1 if INCX .GE. 0, else
C LX = 1+(1-N)*INCX, and similarly for SY using LY and INCY.
C
C With SPARAM(1)=SFLAG, H has one of the following forms:
C
C SFLAG=-1.E0 SFLAG=0.E0 SFLAG=1.E0 SFLAG=-2.E0
C
C (SH11 SH12) (1.E0 SH12) (SH11 1.E0) (1.E0 0.E0)
C H=( ) ( ) ( ) ( )
C (SH21 SH22), (SH21 1.E0), (-1.E0 SH22), (0.E0 1.E0).
C
C See SROTMG for a description of data storage in SPARAM.
C
C***REFERENCES C. L. Lawson, R. J. Hanson, D. R. Kincaid and F. T.
C Krogh, Basic linear algebra subprograms for Fortran
C usage, Algorithm No. 539, Transactions on Mathematical
C Software 5, 3 (September 1979), pp. 308-323.
C***ROUTINES CALLED (NONE)
C***REVISION HISTORY (YYMMDD)
C 791001 DATE WRITTEN
C 861211 REVISION DATE from Version 3.2
C 891214 Prologue converted to Version 4.0 format. (BAB)
C 920310 Corrected definition of LX in DESCRIPTION. (WRB)
C 920501 Reformatted the REFERENCES section. (WRB)
C***END PROLOGUE SROTM