/sys$common/syshlp/helplib.hlb FORTRAN, Intrinsic Procedures, xROTG  *Conan The Librarian (sorry for the slow response - running on an old VAX)

  SROTG (a, b, c, s)
  DROTG (a, b, c, s)
  CROTG (a, b, c, s)
  ZROTG (a, b, c, s)

  Subroutines that generate the elements for a Givens plane rotation.
  These subroutines cannot be inlined.

  These routines are part of the BLAS1 Basic Set, and are only
  available on VAX processors.

  Arguments

    a

    On entry, first element of the input array.  On exit, rotated
    element r.  The data type is REAL*4 for SROTG, REAL*8 for DROTG,
    COMPLEX*8 for CROTG, COMPLEX*16 for ZROTG.

    b

    On entry, second element of the input array.  On exit from SROTG
    and DROTG, reconstruction element z.  The data type is REAL*4 for
    SROTG, REAL*8 for DROTG, COMPLEX*8 for CROTG, COMPLEX*16 for
    ZROTG.

    c

    Variable into which is stored the first rotation element, which
    can be interpreted as the cosine of the angle of rotation.  The
    data type is REAL*4 for SROTG and CROTG, REAL*8 for DROTG and
    ZROTG.

    s

    Variable into which is stored the second rotation element, which
    can be interpreted as the sine of the angle of rotation.  The
    data type is REAL*4 for SROTG, REAL*8 for DROTG, COMPLEX*8 for
    CROTG, COMPLEX*16 for ZROTG.