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Annotation of rpl/lapack/blas/zrotg.f, revision 1.7

1.1       bertrand    1:       SUBROUTINE ZROTG(CA,CB,C,S)
                      2: *     .. Scalar Arguments ..
                      3:       DOUBLE COMPLEX CA,CB,S
                      4:       DOUBLE PRECISION C
                      5: *     ..
                      6: *
                      7: *  Purpose
                      8: *  =======
                      9: *
                     10: *     ZROTG determines a double complex Givens rotation.
                     11: *
                     12: *  =====================================================================
                     13: *
                     14: *     .. Local Scalars ..
                     15:       DOUBLE COMPLEX ALPHA
                     16:       DOUBLE PRECISION NORM,SCALE
                     17: *     ..
                     18: *     .. Intrinsic Functions ..
                     19:       INTRINSIC CDABS,DCMPLX,DCONJG,DSQRT
                     20: *     ..
1.7     ! bertrand   21:       IF (CDABS(CA).EQ.0.0d0) THEN
        !            22:          C = 0.0d0
        !            23:          S = (1.0d0,0.0d0)
        !            24:          CA = CB
        !            25:       ELSE
        !            26:          SCALE = CDABS(CA) + CDABS(CB)
        !            27:          NORM = SCALE*DSQRT((CDABS(CA/DCMPLX(SCALE,0.0d0)))**2+
        !            28:      $       (CDABS(CB/DCMPLX(SCALE,0.0d0)))**2)
        !            29:          ALPHA = CA/CDABS(CA)
        !            30:          C = CDABS(CA)/NORM
        !            31:          S = ALPHA*DCONJG(CB)/NORM
        !            32:          CA = ALPHA*NORM
        !            33:       END IF
1.1       bertrand   34:       RETURN
                     35:       END