• NAME
• SYNOPSIS
• F95 INTERFACE
• C INTERFACE
• PURPOSE
• ARGUMENTS

NAME

zrotg - Construct a Given's plane rotation

SYNOPSIS

  SUBROUTINE ZROTG( A, B, C, S)
  DOUBLE COMPLEX A, B, S
  DOUBLE PRECISION C

  SUBROUTINE ZROTG_64( A, B, C, S)
  DOUBLE COMPLEX A, B, S
  DOUBLE PRECISION C

F95 INTERFACE

  SUBROUTINE ROTG( A, B, C, S)
  COMPLEX(8) :: A, B, S
  REAL(8) :: C

  SUBROUTINE ROTG_64( A, B, C, S)
  COMPLEX(8) :: A, B, S
  REAL(8) :: C

C INTERFACE

#include <sunperf.h>

void zrotg(doublecomplex *a, doublecomplex b, double *c, doublecomplex *s);

void zrotg_64(doublecomplex *a, doublecomplex b, double *c, doublecomplex *s);

PURPOSE

zrotg Construct a Given's plane rotation that will annihilate an element of a vector.

ARGUMENTS

• 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)
  On entry, B contains the entry to be annihilated in the second vector. Unchanged on exit.

• C (output)
  On exit, C and S are the elements of the rotation matrix that will be applied to annihilate B.

• S (output)
  On exit, C and S are the elements of the rotation matrix that will be applied to annihilate B.