1*> \brief \b DCOPY 2* 3* =========== DOCUMENTATION =========== 4* 5* Online html documentation available at 6* http://www.netlib.org/lapack/explore-html/ 7* 8* Definition: 9* =========== 10* 11* SUBROUTINE DCOPY(N,DX,INCX,DY,INCY) 12* 13* .. Scalar Arguments .. 14* INTEGER INCX,INCY,N 15* .. 16* .. Array Arguments .. 17* DOUBLE PRECISION DX(*),DY(*) 18* .. 19* 20* 21*> \par Purpose: 22* ============= 23*> 24*> \verbatim 25*> 26*> DCOPY copies a vector, x, to a vector, y. 27*> uses unrolled loops for increments equal to one. 28*> \endverbatim 29* 30* Authors: 31* ======== 32* 33*> \author Univ. of Tennessee 34*> \author Univ. of California Berkeley 35*> \author Univ. of Colorado Denver 36*> \author NAG Ltd. 37* 38*> \date November 2011 39* 40*> \ingroup double_blas_level1 41* 42*> \par Further Details: 43* ===================== 44*> 45*> \verbatim 46*> 47*> jack dongarra, linpack, 3/11/78. 48*> modified 12/3/93, array(1) declarations changed to array(*) 49*> \endverbatim 50*> 51* ===================================================================== 52 SUBROUTINE DCOPY(N,DX,INCX,DY,INCY) 53* 54* -- Reference BLAS level1 routine (version 3.4.0) -- 55* -- Reference BLAS is a software package provided by Univ. of Tennessee, -- 56* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..-- 57* November 2011 58* 59* .. Scalar Arguments .. 60 INTEGER INCX,INCY,N 61* .. 62* .. Array Arguments .. 63 DOUBLE PRECISION DX(*),DY(*) 64* .. 65* 66* ===================================================================== 67* 68* .. Local Scalars .. 69 INTEGER I,IX,IY,M,MP1 70* .. 71* .. Intrinsic Functions .. 72 INTRINSIC MOD 73* .. 74 IF (N.LE.0) RETURN 75 IF (INCX.EQ.1 .AND. INCY.EQ.1) THEN 76* 77* code for both increments equal to 1 78* 79* 80* clean-up loop 81* 82 M = MOD(N,7) 83 IF (M.NE.0) THEN 84 DO I = 1,M 85 DY(I) = DX(I) 86 END DO 87 IF (N.LT.7) RETURN 88 END IF 89 MP1 = M + 1 90 DO I = MP1,N,7 91 DY(I) = DX(I) 92 DY(I+1) = DX(I+1) 93 DY(I+2) = DX(I+2) 94 DY(I+3) = DX(I+3) 95 DY(I+4) = DX(I+4) 96 DY(I+5) = DX(I+5) 97 DY(I+6) = DX(I+6) 98 END DO 99 ELSE 100* 101* code for unequal increments or equal increments 102* not equal to 1 103* 104 IX = 1 105 IY = 1 106 IF (INCX.LT.0) IX = (-N+1)*INCX + 1 107 IF (INCY.LT.0) IY = (-N+1)*INCY + 1 108 DO I = 1,N 109 DY(IY) = DX(IX) 110 IX = IX + INCX 111 IY = IY + INCY 112 END DO 113 END IF 114 RETURN 115 END 116