Annotation of rpl/lapack/blas/dasum.f, revision 1.1
1.1 ! bertrand 1: DOUBLE PRECISION FUNCTION DASUM(N,DX,INCX)
! 2: * .. Scalar Arguments ..
! 3: INTEGER INCX,N
! 4: * ..
! 5: * .. Array Arguments ..
! 6: DOUBLE PRECISION DX(*)
! 7: * ..
! 8: *
! 9: * Purpose
! 10: * =======
! 11: *
! 12: * DASUM takes the sum of the absolute values.
! 13: *
! 14: * Further Details
! 15: * ===============
! 16: *
! 17: * jack dongarra, linpack, 3/11/78.
! 18: * modified 3/93 to return if incx .le. 0.
! 19: * modified 12/3/93, array(1) declarations changed to array(*)
! 20: *
! 21: * =====================================================================
! 22: *
! 23: * .. Local Scalars ..
! 24: DOUBLE PRECISION DTEMP
! 25: INTEGER I,M,MP1,NINCX
! 26: * ..
! 27: * .. Intrinsic Functions ..
! 28: INTRINSIC DABS,MOD
! 29: * ..
! 30: DASUM = 0.0d0
! 31: DTEMP = 0.0d0
! 32: IF (N.LE.0 .OR. INCX.LE.0) RETURN
! 33: IF (INCX.EQ.1) GO TO 20
! 34: *
! 35: * code for increment not equal to 1
! 36: *
! 37: NINCX = N*INCX
! 38: DO 10 I = 1,NINCX,INCX
! 39: DTEMP = DTEMP + DABS(DX(I))
! 40: 10 CONTINUE
! 41: DASUM = DTEMP
! 42: RETURN
! 43: *
! 44: * code for increment equal to 1
! 45: *
! 46: *
! 47: * clean-up loop
! 48: *
! 49: 20 M = MOD(N,6)
! 50: IF (M.EQ.0) GO TO 40
! 51: DO 30 I = 1,M
! 52: DTEMP = DTEMP + DABS(DX(I))
! 53: 30 CONTINUE
! 54: IF (N.LT.6) GO TO 60
! 55: 40 MP1 = M + 1
! 56: DO 50 I = MP1,N,6
! 57: DTEMP = DTEMP + DABS(DX(I)) + DABS(DX(I+1)) + DABS(DX(I+2)) +
! 58: + DABS(DX(I+3)) + DABS(DX(I+4)) + DABS(DX(I+5))
! 59: 50 CONTINUE
! 60: 60 DASUM = DTEMP
! 61: RETURN
! 62: END
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