ZLARGV
November 2006
Purpose
ZLARGV generates a vector of complex plane rotations with real
cosines, determined by elements of the complex vectors x and y.
For i = 1,2,...,n
( c(i) s(i) ) ( x(i) ) = ( r(i) )
( -conjg(s(i)) c(i) ) ( y(i) ) = ( 0 )
where c(i)**2 + ABS(s(i))**2 = 1
The following conventions are used (these are the same as in ZLARTG,
but differ from the BLAS1 routine ZROTG):
If y(i)=0, then c(i)=1 and s(i)=0.
If x(i)=0, then c(i)=0 and s(i) is chosen so that r(i) is real.
cosines, determined by elements of the complex vectors x and y.
For i = 1,2,...,n
( c(i) s(i) ) ( x(i) ) = ( r(i) )
( -conjg(s(i)) c(i) ) ( y(i) ) = ( 0 )
where c(i)**2 + ABS(s(i))**2 = 1
The following conventions are used (these are the same as in ZLARTG,
but differ from the BLAS1 routine ZROTG):
If y(i)=0, then c(i)=1 and s(i)=0.
If x(i)=0, then c(i)=0 and s(i) is chosen so that r(i) is real.
Arguments
| N |
(input) INTEGER
The number of plane rotations to be generated.
|
| X |
(input/output) COMPLEX*16 array, dimension (1+(N-1)*INCX)
On entry, the vector x.
On exit, x(i) is overwritten by r(i), for i = 1,...,n. |
| INCX |
(input) INTEGER
The increment between elements of X. INCX > 0.
|
| Y |
(input/output) COMPLEX*16 array, dimension (1+(N-1)*INCY)
On entry, the vector y.
On exit, the sines of the plane rotations. |
| INCY |
(input) INTEGER
The increment between elements of Y. INCY > 0.
|
| C |
(output) DOUBLE PRECISION array, dimension (1+(N-1)*INCC)
The cosines of the plane rotations.
|
| INCC |
(input) INTEGER
The increment between elements of C. INCC > 0.
|
Further Details
6-6-96 - Modified with a new algorithm by W. Kahan and J. Demmel
This version has a few statements commented out for thread safety
(machine parameters are computed on each entry). 10 feb 03, SJH.
This version has a few statements commented out for thread safety
(machine parameters are computed on each entry). 10 feb 03, SJH.