71 lines
1.6 KiB
FortranFixed
71 lines
1.6 KiB
FortranFixed
SUBROUTINE DCOPY(N,DX,INCX,DY,INCY)
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* .. Scalar Arguments ..
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INTEGER INCX,INCY,N
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* ..
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* .. Array Arguments ..
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DOUBLE PRECISION DX(*),DY(*)
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* ..
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*
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* Purpose
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* =======
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*
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* DCOPY copies a vector, x, to a vector, y.
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* uses unrolled loops for increments equal to one.
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*
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* Further Details
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* ===============
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*
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* jack dongarra, linpack, 3/11/78.
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* modified 12/3/93, array(1) declarations changed to array(*)
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*
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* =====================================================================
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*
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* .. Local Scalars ..
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INTEGER I,IX,IY,M,MP1
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* ..
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* .. Intrinsic Functions ..
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INTRINSIC MOD
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* ..
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IF (N.LE.0) RETURN
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IF (INCX.EQ.1 .AND. INCY.EQ.1) THEN
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*
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* code for both increments equal to 1
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*
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*
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* clean-up loop
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*
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M = MOD(N,7)
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IF (M.NE.0) THEN
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DO I = 1,M
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DY(I) = DX(I)
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END DO
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IF (N.LT.7) RETURN
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END IF
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MP1 = M + 1
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DO I = MP1,N,7
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DY(I) = DX(I)
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DY(I+1) = DX(I+1)
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DY(I+2) = DX(I+2)
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DY(I+3) = DX(I+3)
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DY(I+4) = DX(I+4)
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DY(I+5) = DX(I+5)
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DY(I+6) = DX(I+6)
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END DO
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ELSE
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*
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* code for unequal increments or equal increments
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* not equal to 1
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*
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IX = 1
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IY = 1
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IF (INCX.LT.0) IX = (-N+1)*INCX + 1
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IF (INCY.LT.0) IY = (-N+1)*INCY + 1
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DO I = 1,N
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DY(IY) = DX(IX)
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IX = IX + INCX
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IY = IY + INCY
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END DO
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END IF
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RETURN
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END
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