?largv

Generates a vector of plane rotations with real cosines and real/complex sines.

Syntax

call slargv( n, x, incx, y, incy, c, incc )

call dlargv( n, x, incx, y, incy, c, incc )

call clargv( n, x, incx, y, incy, c, incc )

call zlargv( n, x, incx, y, incy, c, incc )

Include Files

  • Fortran: mkl.fi
  • C: mkl.h

Description

The routine generates a vector of real/complex plane rotations with real cosines, determined by elements of the real/complex vectors x and y.

For slargv/dlargv:


Equation

For clargv/zlargv:


Equation

where c(i)2 + abs(s(i))2 = 1 and the following conventions are used (these are the same as in clartg/zlartg but differ from the BLAS Level 1 routine crotg/zrotg):

If yi = 0, then c(i) = 1 and s(i) = 0;

If xi = 0, then c(i) = 0 and s(i) is chosen so that ri is real.

Input Parameters

n

INTEGER. The number of plane rotations to be generated.

x, y

REAL for slargv

DOUBLE PRECISION for dlargv

COMPLEX for clargv

DOUBLE COMPLEX for zlargv

Arrays, DIMENSION (1+(n-1)*incx) and (1+(n-1)*incy), respectively. On entry, the vectors x and y.

incx

INTEGER. The increment between elements of x.

incx > 0.

incy

INTEGER. The increment between elements of y.

incy > 0.

incc

INTEGER. The increment between elements of the output array c. incc > 0.

Output Parameters

x

On exit, x(i) is overwritten by ai (for real flavors), or by ri (for complex flavors), for i = 1,...,n.

y

On exit, the sines s(i) of the plane rotations.

c

REAL for slargv/clargv

DOUBLE PRECISION for dlargv/zlargv

Array, DIMENSION (1+(n-1)*incc). The cosines of the plane rotations.

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