sroti(3P) Sun Performance Library sroti(3P)NAMEsroti - Apply an indexed Givens rotation.
SYNOPSIS
SUBROUTINE SROTI(NZ, X, INDX, Y, C, S)
INTEGER NZ
INTEGER INDX(*)
REAL C, S
REAL X(*), Y(*)
SUBROUTINE SROTI_64(NZ, X, INDX, Y, C, S)
INTEGER*8 NZ
INTEGER*8 INDX(*)
REAL C, S
REAL X(*), Y(*)
F95 INTERFACE
SUBROUTINE ROTI([NZ], X, INDX, Y, C, S)
INTEGER :: NZ
INTEGER, DIMENSION(:) :: INDX
REAL :: C, S
REAL, DIMENSION(:) :: X, Y
SUBROUTINE ROTI_64([NZ], X, INDX, Y, C, S)
INTEGER(8) :: NZ
INTEGER(8), DIMENSION(:) :: INDX
REAL :: C, S
REAL, DIMENSION(:) :: X, Y
C INTERFACE
#include <sunperf.h>
void sroti (const int nz, const float* x, const int* indx, float* y,
const float c, const float s);
void sroti_64 (const long nz, const float* x, const long* indx, float*
y, const float c, const float s);
PURPOSE
SROTI - Applies a Givens rotation to a sparse vector x stored in com‐
pressed form and another vector y in full storage form
do i = 1, n
temp = -s * x(i) + c * y(indx(i))
x(i) = c * x(i) + s * y(indx(i))
y(indx(i)) = temp
enddo
ARGUMENTS
NZ (input) - INTEGER
Number of elements in the compressed form. Unchanged on exit.
X (input)
Vector containing the values of the compressed form.
INDX (input) - INTEGER
Vector containing the indices of the compressed form. It is
assumed that the elements in INDX are distinct and greater than
zero. Unchanged on exit.
Y (input/output)
Vector on input which contains the vector Y in full storage
form. On exit, only the elements corresponding to the indices
in INDX have been modified.
C (input)
Scalar defining the Givens rotation
S (input)
Scalar defining the Givens rotation
3rd Berkeley Distribution 6 Mar 2009 sroti(3P)
