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source_hpr2.h

/* blas/source_hpr2.h
 *
 * Copyright (C) 1996, 1997, 1998, 1999, 2000 Gerard Jungman
 *
 * 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 i, j;
  const int conj = (order == CblasColMajor) ? -1 : 1;

  CHECK_ARGS9(CZ_HPR2,order,Uplo,N,alpha,X,incX,Y,incY,Ap);

  {
    const BASE alpha_real = CONST_REAL0(alpha);
    const BASE alpha_imag = CONST_IMAG0(alpha);

    if (alpha_real == 0.0 && alpha_imag == 0.0)
      return;

    if ((order == CblasRowMajor && Uplo == CblasUpper)
        || (order == CblasColMajor && Uplo == CblasLower)) {
      INDEX ix = OFFSET(N, incX);
      INDEX iy = OFFSET(N, incY);
      for (i = 0; i < N; i++) {
        const BASE Xi_real = CONST_REAL(X, ix);
        const BASE Xi_imag = CONST_IMAG(X, ix);
        /* tmp1 = alpha Xi */
        const BASE tmp1_real = alpha_real * Xi_real - alpha_imag * Xi_imag;
        const BASE tmp1_imag = alpha_imag * Xi_real + alpha_real * Xi_imag;

        const BASE Yi_real = CONST_REAL(Y, iy);
        const BASE Yi_imag = CONST_IMAG(Y, iy);
        /* tmp2 = conj(alpha) Yi */
        const BASE tmp2_real = alpha_real * Yi_real + alpha_imag * Yi_imag;
        const BASE tmp2_imag = -alpha_imag * Yi_real + alpha_real * Yi_imag;

        INDEX jx = ix + incX;
        INDEX jy = iy + incY;

        /* Aij = alpha*Xi*conj(Yj) + conj(alpha)*Yi*conj(Xj) */

        REAL(Ap, TPUP(N, i, i)) += 2 * (tmp1_real * Yi_real + tmp1_imag * Yi_imag);
        IMAG(Ap, TPUP(N, i, i)) = 0;

        for (j = i + 1; j < N; j++) {
          const BASE Xj_real = CONST_REAL(X, jx);
          const BASE Xj_imag = CONST_IMAG(X, jx);
          const BASE Yj_real = CONST_REAL(Y, jy);
          const BASE Yj_imag = CONST_IMAG(Y, jy);
          REAL(Ap, TPUP(N, i, j)) += ((tmp1_real * Yj_real + tmp1_imag * Yj_imag)
                                      + (tmp2_real * Xj_real + tmp2_imag * Xj_imag));
          IMAG(Ap, TPUP(N, i, j)) +=
            conj * ((tmp1_imag * Yj_real - tmp1_real * Yj_imag) +
                    (tmp2_imag * Xj_real - tmp2_real * Xj_imag));
          jx += incX;
          jy += incY;
        }
        ix += incX;
        iy += incY;
      }
    } else if ((order == CblasRowMajor && Uplo == CblasLower)
               || (order == CblasColMajor && Uplo == CblasUpper)) {

      INDEX ix = OFFSET(N, incX);
      INDEX iy = OFFSET(N, incY);
      for (i = 0; i < N; i++) {
        const BASE Xi_real = CONST_REAL(X, ix);
        const BASE Xi_imag = CONST_IMAG(X, ix);
        const BASE tmp1_real = alpha_real * Xi_real - alpha_imag * Xi_imag;
        const BASE tmp1_imag = alpha_imag * Xi_real + alpha_real * Xi_imag;

        const BASE Yi_real = CONST_REAL(Y, iy);
        const BASE Yi_imag = CONST_IMAG(Y, iy);
        const BASE tmp2_real = alpha_real * Yi_real + alpha_imag * Yi_imag;
        const BASE tmp2_imag = -alpha_imag * Yi_real + alpha_real * Yi_imag;

        INDEX jx = OFFSET(N, incX);
        INDEX jy = OFFSET(N, incY);

        /* Aij = alpha*Xi*conj(Yj) + conj(alpha)*Yi*conj(Xj) */

        for (j = 0; j < i; j++) {
          const BASE Xj_real = CONST_REAL(X, jx);
          const BASE Xj_imag = CONST_IMAG(X, jx);
          const BASE Yj_real = CONST_REAL(Y, jy);
          const BASE Yj_imag = CONST_IMAG(Y, jy);
          REAL(Ap, TPLO(N, i, j)) += ((tmp1_real * Yj_real + tmp1_imag * Yj_imag)
                                      + (tmp2_real * Xj_real + tmp2_imag * Xj_imag));
          IMAG(Ap, TPLO(N, i, j)) +=
            conj * ((tmp1_imag * Yj_real - tmp1_real * Yj_imag) +
                    (tmp2_imag * Xj_real - tmp2_real * Xj_imag));
          jx += incX;
          jy += incY;
        }

        REAL(Ap, TPLO(N, i, i)) += 2 * (tmp1_real * Yi_real + tmp1_imag * Yi_imag);
        IMAG(Ap, TPLO(N, i, i)) = 0;

        ix += incX;
        iy += incY;
      }
    } else {
      BLAS_ERROR("unrecognized operation");
    }
  }
}

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