Copy a vector.

Copy double precision DX to double precision DY. For I = 0 to N-1, copy DX(LX+I*INCX) to DY(LY+I*INCY), where LX = 1 if INCX .GE. 0, else LX = 1+(1-N)*INCX, and LY is defined in a similar way using INCY.

Usage

dcopy(N = NULL, X, INCX = 1, Y, INCY = 1)

Arguments

N

number of elements in input vector(s)

X

double precision vector with N elements

INCX

storage spacing between elements of DX

Y

double precision vector with N elements

INCY

storage spacing between elements of DY

Value

DY copy of vector DX (unchanged if N .LE. 0)

References

C. L. Lawson, R. J. Hanson, D. R. Kincaid and F. T. Krogh, Basic linear algebra subprograms for Fortran usage, Algorithm No. 539, Transactions on Mathematical Software 5, 3 (September 1979), pp. 308-323.

Examples

set.seed(4669)
A = big.matrix(3, 2, type="double", init=1, dimnames=list(NULL, 
c("alpha", "beta")), shared=FALSE)
B = big.matrix(3, 2, type="double", init=0, dimnames=list(NULL, 
c("alpha", "beta")), shared=FALSE)

dcopy(X=A,Y=B)
#> [1] 0
A[,]-B[,]
#>      alpha beta
#> [1,]     0    0
#> [2,]     0    0
#> [3,]     0    0

# The big.matrix file backings will be deleted when garbage collected.
rm(A,B)
gc()
#>           used (Mb) gc trigger  (Mb) limit (Mb) max used  (Mb)
#> Ncells 1147654 61.3    2286010 122.1         NA  2286010 122.1
#> Vcells 2052770 15.7    8388608  64.0      65536  6482741  49.5