lines 9-100 of file: include/cppad/utility/sparse2eigen.hpp

{xrst_begin sparse2eigen}
{xrst_spell
   nnz
}

Convert A CppAD Sparse Matrix to an Eigen Sparse Matrix
#######################################################

Syntax
******

   # ``include <cppad/utility/sparse2eigen.hpp>``

``sparse2eigen`` ( *source* , *destination* )

Prototype
*********
{xrst_literal
   // BEGIN_PROTOTYPE
   // END_PROTOTYPE
}

Include
*******
If :ref:`cmake@include_eigen` is specified on the cmake command line,
the file ``cppad/utility/sparse2eigen.hpp``
is included by ``cppad/cppad.hpp`` .
In any case,
it can also be included separately with out the rest of
the ``CppAD`` routines.
Including this file defines
this version of the ``sparse2eigen`` within the ``CppAD`` namespace.

SizeVector
**********
We use :ref:`sparse_rc@SizeVector` to denote a
:ref:`SimpleVector-name` class with elements of ``size_t`` .

ValueVector
***********
We use *ValueVector* to denote a
:ref:`SimpleVector-name` class with elements of type *value_type* .

Options
*******
We use *Options* to denote either
``Eigen::RowMajor`` of ``Eigen::ColMajor`` .

value_type
**********
The type of elements of elements in *source* and *destination*
must be the same. We use *value_type* to denote this type.

source
******
This is the CppAD sparse matrix that is being converted to eigen format.

destination
***********
This is the Eigen sparse matrix that is the result of the conversion.

Compressed
**********
The result matrix *destination*
is in compressed format. For example, let

| |tab| ``size_t`` *nnz* = *source* . ``nnz`` ();
| |tab| ``const`` *s_vector* & *s_value* = *source* . ``val`` ();
| |tab| ``const`` *value_type* * *d_value* = *destination* . ``valuePtr`` ();
| |tab| ``const`` *s_vector* & *row_major* = *source* . ``row_major`` ();
| |tab| ``const`` *s_vector* & *col_major* = *source* . ``col_major`` ();

It follows that, for *k* = 0 , ..., *nnz* :
If *Options* is ``Eigen::RowMajor`` ,

   *d_value* [ *k* ] == *s_value* [ *row_major* [ *k* ] ]

If *Options* is ``Eigen::ColMajor`` ,

   *d_value* [ *k* ] == *s_value* [ *col_major* [ *k* ] ]

{xrst_toc_hidden
   example/sparse/sparse2eigen.cpp
}

Example
*******
The file :ref:`sparse2eigen.cpp-name` contains an example and test
of ``sparse2eigen.cpp`` It return true if the test passes
and false otherwise.

{xrst_end sparse2eigen}