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C++ LAPACK::GELS方法代码示例

本文整理汇总了C++中teuchos::LAPACK::GELS方法的典型用法代码示例。如果您正苦于以下问题:C++ LAPACK::GELS方法的具体用法?C++ LAPACK::GELS怎么用?C++ LAPACK::GELS使用的例子?那么恭喜您, 这里精选的方法代码示例或许可以为您提供帮助。您也可以进一步了解该方法所在teuchos::LAPACK的用法示例。


在下文中一共展示了LAPACK::GELS方法的1个代码示例,这些例子默认根据受欢迎程度排序。您可以为喜欢或者感觉有用的代码点赞,您的评价将有助于系统推荐出更棒的C++代码示例。

示例1: Compute


//.........这里部分代码省略.........
  cpts.push_back(zero);

#ifdef HAVE_TEUCHOS_COMPLEX
  const std::complex<double> one(1.0,0.0);

  // Construct overdetermined Vandermonde matrix
  Teuchos::SerialDenseMatrix<int, std::complex<double> > Vmatrix(cpts.size(),PolyDegree_+1);
  Vmatrix.putScalar(zero);
  for (int jj = 0; jj <= PolyDegree_; ++jj) {
    for (int ii = 0; ii < static_cast<int> (cpts.size ()) - 1; ++ii) {
      if (jj > 0) {
        Vmatrix(ii,jj) = pow(cpts[ii],jj);
      }
      else {
        Vmatrix(ii,jj) = one;
      }
    }
  }
  Vmatrix(cpts.size()-1,0)=one;

  // Right hand side: all zero except last entry
  Teuchos::SerialDenseMatrix< int,std::complex<double> > RHS(cpts.size(),1);
  RHS.putScalar(zero);
  RHS(cpts.size()-1,0)=one;

  // Solve least squares problem using LAPACK
  Teuchos::LAPACK< int, std::complex<double> > lapack;
  const int N = Vmatrix.numCols();
  Teuchos::Array<double> singularValues(N);
  Teuchos::Array<double> rwork(1);
  rwork.resize (std::max (1, 5 * N));
  std::complex<double> lworkScalar(1.0,0.0);
  int info = 0;
  lapack.GELS('N', Vmatrix.numRows(), Vmatrix.numCols(), RHS.numCols(),
                   Vmatrix.values(),  Vmatrix.numRows(), RHS.values(),    RHS.numRows(),
                   &lworkScalar, -1, &info);
  TEUCHOS_TEST_FOR_EXCEPTION(info != 0, std::logic_error,
                             "_GELSS workspace query returned INFO = "
                             << info << " != 0.");
  const int lwork = static_cast<int> (real(lworkScalar));
  TEUCHOS_TEST_FOR_EXCEPTION(lwork < 0, std::logic_error,
                             "_GELSS workspace query returned LWORK = "
                             << lwork << " < 0.");
  // Allocate workspace.  Size > 0 means &work[0] makes sense.
  Teuchos::Array< std::complex<double> > work (std::max (1, lwork));
  // Solve the least-squares problem.
  lapack.GELS('N', Vmatrix.numRows(), Vmatrix.numCols(),  RHS.numCols(),
                   Vmatrix.values(),  Vmatrix.numRows(),  RHS.values(),   RHS.numRows(),
                   &work[0], lwork, &info);

  coeff_.resize(PolyDegree_+1);
  std::complex<double> c0=RHS(0,0);
  for(int ii=0; ii<=PolyDegree_; ii++) {
    // test that the imaginary part is nonzero
    //TEUCHOS_TEST_FOR_EXCEPTION(abs(imag(RHS(ii,0))) > 1e-8, std::logic_error,
    //                         "imaginary part of polynomial coefficients is nonzero! coeff = "
    //                         << RHS(ii,0));
    coeff_[ii]=real(RHS(ii,0)/c0);
    //std::cout<<"coeff["<<ii<<"]="<<coeff_[ii]<<std::endl;
  }

#else

  // Construct overdetermined Vandermonde matrix
  Teuchos::SerialDenseMatrix< int, double > Vmatrix(xs.size()+1,PolyDegree_+1);
  Vmatrix.putScalar(0.0);
开发者ID:brian-kelley,项目名称:Trilinos,代码行数:67,代码来源:Ifpack_Polynomial.cpp


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