drotg(3P) Sun Performance Library drotg(3P)NAMEdrotg - Construct a Given's plane rotation
SYNOPSIS
SUBROUTINE DROTG(A, B, C, S)
DOUBLE PRECISION A, B, C, S
SUBROUTINE DROTG_64(A, B, C, S)
DOUBLE PRECISION A, B, C, S
F95 INTERFACE
SUBROUTINE ROTG(A, B, C, S)
REAL(8) :: A, B, C, S
SUBROUTINE ROTG_64(A, B, C, S)
REAL(8) :: A, B, C, S
C INTERFACE
#include <sunperf.h>
void drotg(double *a, double *b, double *c, double *s);
void drotg_64(double *a, double *b, double *c, double *s);
PURPOSEdrotg Construct a Given's plane rotation that will annihilate an ele‐
ment of a vector.
ARGUMENTS
A (input/output)
On entry, A contains the entry in the first vector that cor‐
responds to the element to be annihilated in the second vec‐
tor. On exit, contains the nonzero element of the rotated
vector.
B (input/output)
On entry, B contains the entry to be annihilated in the sec‐
ond vector. On exit, contains either S or 1/C depending on
which of the input values of A and B is larger.
C (output)
On exit, C and S are the elements of the rotation matrix that
will be applied to annihilate B.
S (output)
See the description of C.
6 Mar 2009 drotg(3P)