drotg - Construct a Given's plane rotation
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
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
#include <sunperf.h>
void drotg(double *a, double *b, double *c, double *s);
void drotg_64(double *a, double *b, double *c, double *s);
drotg Construct a Given's plane rotation that will annihilate an element
of a vector.
- A (input/output)
On entry, A contains the entry in the first vector that corresponds to the
element to be annihilated in the second vector. On exit, contains the nonzero
element of the rotated vector.
- B (input/output)
On entry, B contains the entry to be annihilated in the second 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.