expose-function-ops.cpp

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#include "aligator/python/fwd.hpp"
#include "aligator/python/eigen-member.hpp"
#include "aligator/modelling/function-xpr-slice.hpp"
#include "aligator/modelling/linear-function-composition.hpp"
 
namespace aligator {
namespace python {
 
using context::MatrixXs;
using context::Scalar;
using context::StageFunction;
using context::StageFunctionData;
using context::UnaryFunction;
using context::VectorXs;
 
template <typename Base> void exposeSliceExpression(const char *name) {
  // FUNCTION SLICE
 
  using FunctionSliceXpr = FunctionSliceXprTpl<Scalar, Base>;
 
  bp::register_ptr_to_python<shared_ptr<FunctionSliceXpr>>();
  bp::class_<FunctionSliceXpr, bp::bases<Base>>(
      name,
      "Represents a slice of an expression according to either a single index "
      "or an array of indices.",
      bp::init<shared_ptr<Base>, std::vector<int> const &>(
          bp::args("self", "func", "indices")))
      .def(bp::init<shared_ptr<Base>, const int>(
          "Constructor from a single index.", bp::args("self", "func", "idx")))
      .def_readonly("func", &FunctionSliceXpr::func, "Underlying function.")
      .def_readonly("indices", &FunctionSliceXpr::indices,
                    "Indices of the slice.");
}
 
template <typename LFC>
struct LinFunctionCompositionVisitor
    : bp::def_visitor<LinFunctionCompositionVisitor<LFC>> {
  using FunType = typename LFC::Base;
 
  template <class PyClass> void visit(PyClass &cl) const {
    cl.def(bp::init<shared_ptr<FunType>, const MatrixXs, const VectorXs>(
               "Construct a composition from the underlying function, weight "
               "matrix "
               ":math:`A` and bias :math:`b`.",
               bp::args("self", "func", "A", "b")))
        .def(bp::init<shared_ptr<FunType>, const context::MatrixXs>(
            "Constructor where the bias :math:`b` is assumed to be zero.",
            bp::args("self", "func", "A")))
        .def_readonly("func", &LFC::func, "The underlying function.")
        .def_readonly("A", &LFC::A, "Weight matrix.")
        .def_readonly("b", &LFC::b, "Bias vector.");
    bp::class_<typename LFC::Data, bp::bases<StageFunctionData>,
               boost::noncopyable>("LFC", bp::no_init)
        .def_readonly("sub_data", &LFC::Data::sub_data);
 
    bp::def(
        "linear_compose",
        +[](shared_ptr<FunType> func, const MatrixXs &A, const VectorXs &b) {
          return linear_compose(func, A, b);
        },
        bp::args("func", "A", "b"));
  }
};
 
void exposeFunctionExpressions() {
 
  exposeSliceExpression<StageFunction>("StageFunctionSliceXpr");
  exposeSliceExpression<UnaryFunction>("UnaryFunctionSliceXpr");
 
  using FunctionSliceData = FunctionSliceDataTpl<Scalar>;
  bp::class_<FunctionSliceData, bp::bases<StageFunctionData>,
             boost::noncopyable>("FunctionSliceData", bp::no_init)
      .def_readonly("sub_data", &FunctionSliceData::sub_data,
                    "Underlying function's data.");
 
 
  using LinearFunctionComposition = LinearFunctionCompositionTpl<Scalar>;
  using LinearUnaryFunctionComposition =
      LinearUnaryFunctionCompositionTpl<Scalar>;
 
  bp::register_ptr_to_python<shared_ptr<LinearFunctionComposition>>();
  bp::class_<LinearFunctionComposition, bp::bases<StageFunction>>(
      "LinearFunctionComposition",
      "Function composition :math:`r(x) = Af(x, u, y) + b`.", bp::no_init)
      .def(LinFunctionCompositionVisitor<LinearFunctionComposition>());
 
  bp::register_ptr_to_python<shared_ptr<LinearUnaryFunctionComposition>>();
  bp::class_<LinearUnaryFunctionComposition, bp::bases<UnaryFunction>>(
      "LinearUnaryFunctionComposition",
      "Function composition for unary functions: :math:`r(x) = Af(x) + b`.",
      bp::no_init)
      .def(LinFunctionCompositionVisitor<LinearUnaryFunctionComposition>());
}
 
} // namespace python
} // namespace aligator