/* blas/source_rotm.h

 * 

 * Copyright (C) 1996, 1997, 1998, 1999, 2000, 2007 Brian Gough

 * 

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation; either version 3 of the License, or (at

 * your option) any later version.

 * 

 * This program is distributed in the hope that it will be useful, but

 * WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

 * General Public License for more details.

 * 

 * You should have received a copy of the GNU General Public License

 * along with this program; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.

 */

{

  INDEX n;

  INDEX i = OFFSET(N, incX);

  INDEX j = OFFSET(N, incY);

  BASE h11, h21, h12, h22;

  if (P[0] == -1.0) {

    h11 = P[1];

    h21 = P[2];

    h12 = P[3];

    h22 = P[4];

  } else if (P[0] == 0.0) {

    h11 = 1.0;

    h21 = P[2];

    h12 = P[3];

    h22 = 1.0;

  } else if (P[0] == 1.0) {

    h11 = P[1];

    h21 = -1.0;

    h12 = 1.0;

    h22 = P[4];

  } else if (P[0] == -2.0) {

    return;

  } else {

    BLAS_ERROR("unrecognized value of P[0]");

    return;

  }

  for (n = 0; n < N; n++) {

    const BASE w = X[i];

    const BASE z = Y[j];

    X[i] = h11 * w + h12 * z;

    Y[j] = h21 * w + h22 * z;

    i += incX;

    j += incY;

  }

}