Annotation of rpl/lapack/blas/zrotg.f, revision 1.1
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: * ..
! 21: IF (CDABS(CA).NE.0.0d0) GO TO 10
! 22: C = 0.0d0
! 23: S = (1.0d0,0.0d0)
! 24: CA = CB
! 25: GO TO 20
! 26: 10 CONTINUE
! 27: SCALE = CDABS(CA) + CDABS(CB)
! 28: NORM = SCALE*DSQRT((CDABS(CA/DCMPLX(SCALE,0.0d0)))**2+
! 29: + (CDABS(CB/DCMPLX(SCALE,0.0d0)))**2)
! 30: ALPHA = CA/CDABS(CA)
! 31: C = CDABS(CA)/NORM
! 32: S = ALPHA*DCONJG(CB)/NORM
! 33: CA = ALPHA*NORM
! 34: 20 CONTINUE
! 35: RETURN
! 36: END
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