text: // This file is part of Eigen, a lightweight C++ template library
  // for linear algebra.
  //
  // Copyright (C) 2009-2010 Gael Guennebaud <gael.guennebaud@inria.fr>
  //
  // This Source Code Form is subject to the terms of the Mozilla
  // Public License v. 2.0. If a copy of the MPL was not distributed
  // with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
  
  #include "common.h"
  
  // y = alpha*A*x + beta*y
  int EIGEN_BLAS_FUNC(symv) (char *uplo, int *n, RealScalar *palpha, RealScalar *pa, int *lda, RealScalar *px, int *incx, RealScalar *pbeta, RealScalar *py, int *incy)
  {
    Scalar* a = reinterpret_cast<Scalar*>(pa);
    Scalar* x = reinterpret_cast<Scalar*>(px);
    Scalar* y = reinterpret_cast<Scalar*>(py);
    Scalar alpha  = *reinterpret_cast<Scalar*>(palpha);
    Scalar beta   = *reinterpret_cast<Scalar*>(pbeta);
  
    // check arguments
    int info = 0;
    if(UPLO(*uplo)==INVALID)        info = 1;
    else if(*n<0)                   info = 2;
    else if(*lda<std::max(1,*n))    info = 5;
    else if(*incx==0)               info = 7;
    else if(*incy==0)               info = 10;
    if(info)
      return xerbla_(SCALAR_SUFFIX_UP"SYMV ",&info,6);
  
    if(*n==0)
      return 0;
  
    Scalar* actual_x = get_compact_vector(x,*n,*incx);
    Scalar* actual_y = get_compact_vector(y,*n,*incy);
  
    if(beta!=Scalar(1))
    {
      if(beta==Scalar(0)) vector(actual_y, *n).setZero();
      else                vector(actual_y, *n) *= beta;
    }
  
    // TODO performs a direct call to the underlying implementation function
         if(UPLO(*uplo)==UP) vector(actual_y,*n).noalias() += matrix(a,*n,*n,*lda).selfadjointView<Upper>() * (alpha * vector(actual_x,*n));
    else if(UPLO(*uplo)==LO) vector(actual_y,*n).noalias() += matrix(a,*n,*n,*lda).selfadjointView<Lower>() * (alpha * vector(actual_x,*n));
  
    if(actual_x!=x) delete[] actual_x;
    if(actual_y!=y) delete[] copy_back(actual_y,y,*n,*incy);
  
    return 1;
  }
  
  // C := alpha*x*x' + C
  int EIGEN_BLAS_FUNC(syr)(char *uplo, int *n, RealScalar *palpha, RealScalar *px, int *incx, RealScalar *pc, int *ldc)
  {
  
  //   typedef void (*functype)(int, const Scalar *, int, Scalar *, int, Scalar);
  //   static functype func[2];
  
  //   static bool init = false;
  //   if(!init)
  //   {
  //     for(int k=0; k<2; ++k)
  //       func[k] = 0;
  //
  //     func[UP] = (internal::selfadjoint_product<Scalar,ColMajor,ColMajor,false,UpperTriangular>::run);
  //     func[LO] = (internal::selfadjoint_product<Scalar,ColMajor,ColMajor,false,LowerTriangular>::run);
  
  //     init = true;
  //   }
  
    Scalar* x = reinterpret_cast<Scalar*>(px);
    Scalar* c = reinterpret_cast<Scalar*>(pc);
    Scalar alpha = *reinterpret_cast<Scalar*>(palpha);
  
    int info = 0;
    if(UPLO(*uplo)==INVALID)                                            info = 1;
    else if(*n<0)                                                       info = 2;
    else if(*incx==0)                                                   info = 5;
    else if(*ldc<std::max(1,*n))                                        info = 7;
    if(info)
      return xerbla_(SCALAR_SUFFIX_UP"SYR  ",&info,6);
  
    if(*n==0 || alpha==Scalar(0)) return 1;
  
    // if the increment is not 1, let's copy it to a temporary vector to enable vectorization
    Scalar* x_cpy = get_compact_vector(x,*n,*incx);
  
    Matrix<Scalar,Dynamic,Dynamic> m2(matrix(c,*n,*n,*ldc));
    
    // TODO check why this is not accurate enough for lapack tests
  //   if(UPLO(*uplo)==LO)       matrix(c,*n,*n,*ldc).selfadjointView<Lower>().rankUpdate(vector(x_cpy,*n), alpha);
  //   else if(UPLO(*uplo)==UP)  matrix(c,*n,*n,*ldc).selfadjointView<Upper>().rankUpdate(vector(x_cpy,*n), alpha);
  
    if(UPLO(*uplo)==LO)
      for(int j=0;j<*n;++j)
        matrix(c,*n,*n,*ldc).col(j).tail(*n-j) += alpha * x_cpy[j] * vector(x_cpy+j,*n-j);
    else
      for(int j=0;j<*n;++j)
        matrix(c,*n,*n,*ldc).col(j).head(j+1) += alpha * x_cpy[j] * vector(x_cpy,j+1);
  
    if(x_cpy!=x)  delete[] x_cpy;
  
    return 1;
  }
  
  // C := alpha*x*y' + alpha*y*x' + C
  int EIGEN_BLAS_FUNC(syr2)(char *uplo, int *n, RealScalar *palpha, RealScalar *px, int *incx, RealScalar *py, int *incy, RealScalar *pc, int *ldc)
  {
  //   typedef void (*functype)(int, const Scalar *, int, const Scalar *, int, Scalar *, int, Scalar);
  //   static functype func[2];
  //
  //   static bool init = false;
  //   if(!init)
  //   {
  //     for(int k=0; k<2; ++k)
  //       func[k] = 0;
  //
  //     func[UP] = (internal::selfadjoint_product<Scalar,ColMajor,ColMajor,false,UpperTriangular>::run);
  //     func[LO] = (internal::selfadjoint_product<Scalar,ColMajor,ColMajor,false,LowerTriangular>::run);
  //
  //     init = true;
  //   }
  
    Scalar* x = reinterpret_cast<Scalar*>(px);
    Scalar* y = reinterpret_cast<Scalar*>(py);
    Scalar* c = reinterpret_cast<Scalar*>(pc);
    Scalar alpha = *reinterpret_cast<Scalar*>(palpha);
  
    int info = 0;
    if(UPLO(*uplo)==INVALID)                                            info = 1;
    else if(*n<0)                                                       info = 2;
    else if(*incx==0)                                                   info = 5;
    else if(*incy==0)                                                   info = 7;
    else if(*ldc<std::max(1,*n))                                        info = 9;
    if(info)
      return xerbla_(SCALAR_SUFFIX_UP"SYR2 ",&info,6);
  
    if(alpha==Scalar(0))
      return 1;
  
    Scalar* x_cpy = get_compact_vector(x,*n,*incx);
    Scalar* y_cpy = get_compact_vector(y,*n,*incy);
  
    // TODO perform direct calls to underlying implementation
    if(UPLO(*uplo)==LO)       matrix(c,*n,*n,*ldc).selfadjointView<Lower>().rankUpdate(vector(x_cpy,*n), vector(y_cpy,*n), alpha);
    else if(UPLO(*uplo)==UP)  matrix(c,*n,*n,*ldc).selfadjointView<Upper>().rankUpdate(vector(x_cpy,*n), vector(y_cpy,*n), alpha);
  
    if(x_cpy!=x)  delete[] x_cpy;
    if(y_cpy!=y)  delete[] y_cpy;
  
  //   int code = UPLO(*uplo);
  //   if(code>=2 || func[code]==0)
  //     return 0;
  
  //   func[code](*n, a, *inca, b, *incb, c, *ldc, alpha);
    return 1;
  }
  
  /**  DSBMV  performs the matrix-vector  operation
    *
    *     y := alpha*A*x + beta*y,
    *
    *  where alpha and beta are scalars, x and y are n element vectors and
    *  A is an n by n symmetric band matrix, with k super-diagonals.
    */
  // int EIGEN_BLAS_FUNC(sbmv)( char *uplo, int *n, int *k, RealScalar *alpha, RealScalar *a, int *lda,
  //                            RealScalar *x, int *incx, RealScalar *beta, RealScalar *y, int *incy)
  // {
  //   return 1;
  // }
  
  
  /**  DSPMV  performs the matrix-vector operation
    *
    *     y := alpha*A*x + beta*y,
    *
    *  where alpha and beta are scalars, x and y are n element vectors and
    *  A is an n by n symmetric matrix, supplied in packed form.
    *
    */
  // int EIGEN_BLAS_FUNC(spmv)(char *uplo, int *n, RealScalar *alpha, RealScalar *ap, RealScalar *x, int *incx, RealScalar *beta, RealScalar *y, int *incy)
  // {
  //   return 1;
  // }
  
  /**  DSPR    performs the symmetric rank 1 operation
    *
    *     A := alpha*x*x' + A,
    *
    *  where alpha is a real scalar, x is an n element vector and A is an
    *  n by n symmetric matrix, supplied in packed form.
    */
  // int EIGEN_BLAS_FUNC(spr)(char *uplo, int *n, Scalar *alpha, Scalar *x, int *incx, Scalar *ap)
  // {
  //   return 1;
  // }
  
  /**  DSPR2  performs the symmetric rank 2 operation
    *
    *     A := alpha*x*y' + alpha*y*x' + A,
    *
    *  where alpha is a scalar, x and y are n element vectors and A is an
    *  n by n symmetric matrix, supplied in packed form.
    */
  // int EIGEN_BLAS_FUNC(spr2)(char *uplo, int *n, RealScalar *alpha, RealScalar *x, int *incx, RealScalar *y, int *incy, RealScalar *ap)
  // {
  //   return 1;
  // }
  
  