Scale a Vector

Calling Sequence

CALL DSCAL	(N, DALPHA, DY, INCY)
CALL SSCAL	(N, SALPHA, SY, INCY)
CALL ZSCAL	(N, ZALPHA, ZY, INCY)
CALL CSCAL	(N, CALPHA, CY, INCY)
CALL ZDSCAL	(N, DALPHA, ZY, INCY)
CALL CSSCAL	(N, SALPHA, CY, INCY)
void dscal	(int n, double da, double *dx, int incx)
void sscal	(int n, float sa, float *sx, int incx)
void zscal	(int n, doublecomplex *za, doublecomplex *zx, int incx)
void cscal	(int n, complex *ca, complex *cx, int incx)
void zdscal	(int n, double da, doublecomplex *zx, int incx)
void csscal	(int n, float sa, complex *cx, int incx)

Arguments

N	Number of elements in the vector. N 0.
xALPHA	Scalar that will be applied to Y.
xY	Input vector Y; the size of array Y must be at least max(1,N*|INCY|).
INCY	Specifies the storage spacing between successive elements of the vector Y. A value of one indicates that the elements of the vector are consecutive in memory. INCY > 0.
	If Y refers to a two-dimensional array and the value of INCY is equal to the leading dimension of Y then the elements of the vector will be a row of Y.
	If Y refers to a two-dimensional array and the value of INCY is equal to the leading dimension of Y plus one then the elements of the vector will be a diagonal of Y.

Sample Program

PROGRAM TEST

IMPLICIT NONE

C

INTEGER N

PARAMETER (N = 3)

C

INTEGER ICOL, INCX, IROW

DOUBLE PRECISION SCALE, X(N,N)

C

EXTERNAL DSCAL

C

C Initialize the array X to store the vector x shown below.

C

C 5.0 5.5 6.0

C x = 2.5 3.0 3.5

C 1.0 1.5 2.0

C

DATA X / 5.0D0, 2.5D0, 1.0D0, 5.5D0, 3.0D0, 1.5D0,

$ 6.0D0, 3.5D0, 2.0D0 /

C

PRINT 1000

PRINT 1010, ((X(IROW,ICOL), ICOL = 1, N), IROW = 1, N)

INCX = N

SCALE = X(1,1) / X(2,1)

CALL DSCAL (N, SCALE, X(2,1), INCX)

PRINT 1020

PRINT 1010, ((X(IROW,ICOL), ICOL = 1, N), IROW = 1, N)

C

1000 FORMAT (1X, 'Before scaling row 2:')

1010 FORMAT (3(3X, F3.1))

1020 FORMAT (/1X, 'After scaling row 2:')

C

END

Sample Output

Before scaling row 2:
5.0 5.5 6.0
2.5 3.0 3.5
1.0 1.5 2.0
After scaling row 2:
5.0 5.5 6.0
5.0 6.0 7.0
1.0 1.5 2.0