\(\newcommand{\W}[1]{ \; #1 \; }\) \(\newcommand{\R}[1]{ {\rm #1} }\) \(\newcommand{\B}[1]{ {\bf #1} }\) \(\newcommand{\D}[2]{ \frac{\partial #1}{\partial #2} }\) \(\newcommand{\DD}[3]{ \frac{\partial^2 #1}{\partial #2 \partial #3} }\) \(\newcommand{\Dpow}[2]{ \frac{\partial^{#1}}{\partial {#2}^{#1}} }\) \(\newcommand{\dpow}[2]{ \frac{ {\rm d}^{#1}}{{\rm d}\, {#2}^{#1}} }\)

atomic_four_vector_jac_sparsity.hpp

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Atomic Vector Jacobian Sparsity Pattern: Example Implementation

Purpose

The jac_sparsity routine overrides the virtual functions used by the atomic_four base class for Jacobian sparsity calculations; see jac_sparsity .

Example

The file atomic_four_vector_jac_sparsity.cpp contains an example and test using this operator.

Source

# include <cppad/example/atomic_four/vector/vector.hpp>

namespace CppAD { // BEGIN_CPPAD_NAMESPACE
//
// jac_sparsity override
template <class Base>
bool atomic_vector<Base>::jac_sparsity(
   size_t                                         call_id      ,
   bool                                           dependency   ,
   const CppAD::vector<bool>&                     ident_zero_x ,
   const CppAD::vector<bool>&                     select_x     ,
   const CppAD::vector<bool>&                     select_y     ,
   CppAD::sparse_rc< CppAD::vector<size_t> >&     pattern_out  )
{
   size_t n = select_x.size();
   size_t m = select_y.size();
   assert( n == m || n == 2 * m );
   //
   // nnz
   // number of non-zeros in sparsity pattern
   size_t nnz = 0;
   for(size_t i = 0; i < m; ++i) if( select_y[i] )
   {  size_t j = i;
      if( select_x[j] )
         ++nnz;
      if( n != m )
      {  // binary operator
         j = m + i;
         if( select_x[j] )
            ++nnz;
      }
   }
   //
   // pattern_out
   pattern_out.resize(m, n, nnz);
   size_t k = 0;
   for(size_t i = 0; i < m; ++i) if( select_y[i] )
   {  size_t j = i;
      if( select_x[j] )
         pattern_out.set(k++, i, j);
      if( n != m )
      {  // binary operator
         j = m + i;
         if( select_x[j] )
            pattern_out.set(k++, i, j);
      }
   }
   assert( k == nnz);
   //
   return true;
}
} // END_CPPAD_NAMESPACE