dsfrk function

Implementation

void dsfrk(
  final String TRANSR,
  final String UPLO,
  final String TRANS,
  final int N,
  final int K,
  final double ALPHA,
  final Matrix<double> A_,
  final int LDA,
  final double BETA,
  final Array<double> C_,
) {
  final A = A_.having(ld: LDA);
  final C = C_.having();
  const ONE = 1.0, ZERO = 0.0;
  bool LOWER, NORMALTRANSR, NISODD, NOTRANS;
  int INFO, NROWA, J, NK = 0, N1 = 0, N2 = 0;

  // Test the input parameters.

  INFO = 0;
  NORMALTRANSR = lsame(TRANSR, 'N');
  LOWER = lsame(UPLO, 'L');
  NOTRANS = lsame(TRANS, 'N');

  if (NOTRANS) {
    NROWA = N;
  } else {
    NROWA = K;
  }

  if (!NORMALTRANSR && !lsame(TRANSR, 'T')) {
    INFO = -1;
  } else if (!LOWER && !lsame(UPLO, 'U')) {
    INFO = -2;
  } else if (!NOTRANS && !lsame(TRANS, 'T')) {
    INFO = -3;
  } else if (N < 0) {
    INFO = -4;
  } else if (K < 0) {
    INFO = -5;
  } else if (LDA < max(1, NROWA)) {
    INFO = -8;
  }
  if (INFO != 0) {
    xerbla('DSFRK', -INFO);
    return;
  }

  // Quick return if possible.

  // The quick return case: ((ALPHA == 0) && (BETA != ZERO)) is not
  // done (it is in DSYRK for example) and left in the general case.

  if ((N == 0) || (((ALPHA == ZERO) || (K == 0)) && (BETA == ONE))) return;

  if ((ALPHA == ZERO) && (BETA == ZERO)) {
    for (J = 1; J <= (N * (N + 1)) ~/ 2; J++) {
      C[J] = ZERO;
    }
    return;
  }

  // C is N-by-N.
  // If N is odd, set NISODD = true , and N1 and N2.
  // If N is even, NISODD = false , and NK.

  if ((N % 2) == 0) {
    NISODD = false;
    NK = N ~/ 2;
  } else {
    NISODD = true;
    if (LOWER) {
      N2 = N ~/ 2;
      N1 = N - N2;
    } else {
      N1 = N ~/ 2;
      N2 = N - N1;
    }
  }

  if (NISODD) {
    // N is odd

    if (NORMALTRANSR) {
      // N is odd and TRANSR = 'N'

      if (LOWER) {
        // N is odd, TRANSR = 'N', and UPLO = 'L'

        if (NOTRANS) {
          // N is odd, TRANSR = 'N', UPLO = 'L', and TRANS = 'N'

          dsyrk(
              'L', 'N', N1, K, ALPHA, A(1, 1), LDA, BETA, C(1).asMatrix(N), N);
          dsyrk('U', 'N', N2, K, ALPHA, A(N1 + 1, 1), LDA, BETA,
              C(N + 1).asMatrix(N), N);
          dgemm('N', 'T', N2, N1, K, ALPHA, A(N1 + 1, 1), LDA, A(1, 1), LDA,
              BETA, C(N1 + 1).asMatrix(N), N);
        } else {
          // N is odd, TRANSR = 'N', UPLO = 'L', and TRANS = 'T'

          dsyrk(
              'L', 'T', N1, K, ALPHA, A(1, 1), LDA, BETA, C(1).asMatrix(N), N);
          dsyrk('U', 'T', N2, K, ALPHA, A(1, N1 + 1), LDA, BETA,
              C(N + 1).asMatrix(N), N);
          dgemm('T', 'N', N2, N1, K, ALPHA, A(1, N1 + 1), LDA, A(1, 1), LDA,
              BETA, C(N1 + 1).asMatrix(N), N);
        }
      } else {
        // N is odd, TRANSR = 'N', and UPLO = 'U'

        if (NOTRANS) {
          // N is odd, TRANSR = 'N', UPLO = 'U', and TRANS = 'N'

          dsyrk('L', 'N', N1, K, ALPHA, A(1, 1), LDA, BETA,
              C(N2 + 1).asMatrix(N), N);
          dsyrk('U', 'N', N2, K, ALPHA, A(N2, 1), LDA, BETA,
              C(N1 + 1).asMatrix(N), N);
          dgemm('N', 'T', N1, N2, K, ALPHA, A(1, 1), LDA, A(N2, 1), LDA, BETA,
              C(1).asMatrix(N), N);
        } else {
          // N is odd, TRANSR = 'N', UPLO = 'U', and TRANS = 'T'

          dsyrk('L', 'T', N1, K, ALPHA, A(1, 1), LDA, BETA,
              C(N2 + 1).asMatrix(N), N);
          dsyrk('U', 'T', N2, K, ALPHA, A(1, N2), LDA, BETA,
              C(N1 + 1).asMatrix(N), N);
          dgemm('T', 'N', N1, N2, K, ALPHA, A(1, 1), LDA, A(1, N2), LDA, BETA,
              C(1).asMatrix(N), N);
        }
      }
    } else {
      // N is odd, and TRANSR = 'T'

      if (LOWER) {
        // N is odd, TRANSR = 'T', and UPLO = 'L'

        if (NOTRANS) {
          // N is odd, TRANSR = 'T', UPLO = 'L', and TRANS = 'N'

          dsyrk('U', 'N', N1, K, ALPHA, A(1, 1), LDA, BETA, C(1).asMatrix(N1),
              N1);
          dsyrk('L', 'N', N2, K, ALPHA, A(N1 + 1, 1), LDA, BETA,
              C(2).asMatrix(N1), N1);
          dgemm('N', 'T', N1, N2, K, ALPHA, A(1, 1), LDA, A(N1 + 1, 1), LDA,
              BETA, C(N1 * N1 + 1).asMatrix(N1), N1);
        } else {
          // N is odd, TRANSR = 'T', UPLO = 'L', and TRANS = 'T'

          dsyrk('U', 'T', N1, K, ALPHA, A(1, 1), LDA, BETA, C(1).asMatrix(N1),
              N1);
          dsyrk('L', 'T', N2, K, ALPHA, A(1, N1 + 1), LDA, BETA,
              C(2).asMatrix(N1), N1);
          dgemm('T', 'N', N1, N2, K, ALPHA, A(1, 1), LDA, A(1, N1 + 1), LDA,
              BETA, C(N1 * N1 + 1).asMatrix(N1), N1);
        }
      } else {
        // N is odd, TRANSR = 'T', and UPLO = 'U'

        if (NOTRANS) {
          // N is odd, TRANSR = 'T', UPLO = 'U', and TRANS = 'N'

          dsyrk('U', 'N', N1, K, ALPHA, A(1, 1), LDA, BETA,
              C(N2 * N2 + 1).asMatrix(N2), N2);
          dsyrk('L', 'N', N2, K, ALPHA, A(N1 + 1, 1), LDA, BETA,
              C(N1 * N2 + 1).asMatrix(N2), N2);
          dgemm('N', 'T', N2, N1, K, ALPHA, A(N1 + 1, 1), LDA, A(1, 1), LDA,
              BETA, C(1).asMatrix(N2), N2);
        } else {
          // N is odd, TRANSR = 'T', UPLO = 'U', and TRANS = 'T'

          dsyrk('U', 'T', N1, K, ALPHA, A(1, 1), LDA, BETA,
              C(N2 * N2 + 1).asMatrix(N2), N2);
          dsyrk('L', 'T', N2, K, ALPHA, A(1, N1 + 1), LDA, BETA,
              C(N1 * N2 + 1).asMatrix(N2), N2);
          dgemm('T', 'N', N2, N1, K, ALPHA, A(1, N1 + 1), LDA, A(1, 1), LDA,
              BETA, C(1).asMatrix(N2), N2);
        }
      }
    }
  } else {
    // N is even

    if (NORMALTRANSR) {
      // N is even and TRANSR = 'N'

      if (LOWER) {
        // N is even, TRANSR = 'N', and UPLO = 'L'

        if (NOTRANS) {
          // N is even, TRANSR = 'N', UPLO = 'L', and TRANS = 'N'

          dsyrk('L', 'N', NK, K, ALPHA, A(1, 1), LDA, BETA,
              C(2).asMatrix(N + 1), N + 1);
          dsyrk('U', 'N', NK, K, ALPHA, A(NK + 1, 1), LDA, BETA,
              C(1).asMatrix(N + 1), N + 1);
          dgemm('N', 'T', NK, NK, K, ALPHA, A(NK + 1, 1), LDA, A(1, 1), LDA,
              BETA, C(NK + 2).asMatrix(N + 1), N + 1);
        } else {
          // N is even, TRANSR = 'N', UPLO = 'L', and TRANS = 'T'

          dsyrk('L', 'T', NK, K, ALPHA, A(1, 1), LDA, BETA,
              C(2).asMatrix(N + 1), N + 1);
          dsyrk('U', 'T', NK, K, ALPHA, A(1, NK + 1), LDA, BETA,
              C(1).asMatrix(N + 1), N + 1);
          dgemm('T', 'N', NK, NK, K, ALPHA, A(1, NK + 1), LDA, A(1, 1), LDA,
              BETA, C(NK + 2).asMatrix(N + 1), N + 1);
        }
      } else {
        // N is even, TRANSR = 'N', and UPLO = 'U'

        if (NOTRANS) {
          // N is even, TRANSR = 'N', UPLO = 'U', and TRANS = 'N'

          dsyrk('L', 'N', NK, K, ALPHA, A(1, 1), LDA, BETA,
              C(NK + 2).asMatrix(N + 1), N + 1);
          dsyrk('U', 'N', NK, K, ALPHA, A(NK + 1, 1), LDA, BETA,
              C(NK + 1).asMatrix(N + 1), N + 1);
          dgemm('N', 'T', NK, NK, K, ALPHA, A(1, 1), LDA, A(NK + 1, 1), LDA,
              BETA, C(1).asMatrix(N + 1), N + 1);
        } else {
          // N is even, TRANSR = 'N', UPLO = 'U', and TRANS = 'T'

          dsyrk('L', 'T', NK, K, ALPHA, A(1, 1), LDA, BETA,
              C(NK + 2).asMatrix(N + 1), N + 1);
          dsyrk('U', 'T', NK, K, ALPHA, A(1, NK + 1), LDA, BETA,
              C(NK + 1).asMatrix(N + 1), N + 1);
          dgemm('T', 'N', NK, NK, K, ALPHA, A(1, 1), LDA, A(1, NK + 1), LDA,
              BETA, C(1).asMatrix(N + 1), N + 1);
        }
      }
    } else {
      // N is even, and TRANSR = 'T'

      if (LOWER) {
        // N is even, TRANSR = 'T', and UPLO = 'L'

        if (NOTRANS) {
          // N is even, TRANSR = 'T', UPLO = 'L', and TRANS = 'N'

          dsyrk('U', 'N', NK, K, ALPHA, A(1, 1), LDA, BETA,
              C(NK + 1).asMatrix(NK), NK);
          dsyrk('L', 'N', NK, K, ALPHA, A(NK + 1, 1), LDA, BETA,
              C(1).asMatrix(NK), NK);
          dgemm('N', 'T', NK, NK, K, ALPHA, A(1, 1), LDA, A(NK + 1, 1), LDA,
              BETA, C(((NK + 1) * NK) + 1).asMatrix(NK), NK);
        } else {
          // N is even, TRANSR = 'T', UPLO = 'L', and TRANS = 'T'

          dsyrk('U', 'T', NK, K, ALPHA, A(1, 1), LDA, BETA,
              C(NK + 1).asMatrix(NK), NK);
          dsyrk('L', 'T', NK, K, ALPHA, A(1, NK + 1), LDA, BETA,
              C(1).asMatrix(NK), NK);
          dgemm('T', 'N', NK, NK, K, ALPHA, A(1, 1), LDA, A(1, NK + 1), LDA,
              BETA, C(((NK + 1) * NK) + 1).asMatrix(NK), NK);
        }
      } else {
        // N is even, TRANSR = 'T', and UPLO = 'U'

        if (NOTRANS) {
          // N is even, TRANSR = 'T', UPLO = 'U', and TRANS = 'N'

          dsyrk('U', 'N', NK, K, ALPHA, A(1, 1), LDA, BETA,
              C(NK * (NK + 1) + 1).asMatrix(NK), NK);
          dsyrk('L', 'N', NK, K, ALPHA, A(NK + 1, 1), LDA, BETA,
              C(NK * NK + 1).asMatrix(NK), NK);
          dgemm('N', 'T', NK, NK, K, ALPHA, A(NK + 1, 1), LDA, A(1, 1), LDA,
              BETA, C(1).asMatrix(NK), NK);
        } else {
          // N is even, TRANSR = 'T', UPLO = 'U', and TRANS = 'T'

          dsyrk('U', 'T', NK, K, ALPHA, A(1, 1), LDA, BETA,
              C(NK * (NK + 1) + 1).asMatrix(NK), NK);
          dsyrk('L', 'T', NK, K, ALPHA, A(1, NK + 1), LDA, BETA,
              C(NK * NK + 1).asMatrix(NK), NK);
          dgemm('T', 'N', NK, NK, K, ALPHA, A(1, NK + 1), LDA, A(1, 1), LDA,
              BETA, C(1).asMatrix(NK), NK);
        }
      }
    }
  }
}