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diff --git a/include/ceres/cost_function.h b/include/ceres/cost_function.h new file mode 100644 index 0000000..9b010f7 --- /dev/null +++ b/include/ceres/cost_function.h @@ -0,0 +1,127 @@ +// Ceres Solver - A fast non-linear least squares minimizer +// Copyright 2010, 2011, 2012 Google Inc. All rights reserved. +// http://code.google.com/p/ceres-solver/ +// +// Redistribution and use in source and binary forms, with or without +// modification, are permitted provided that the following conditions are met: +// +// * Redistributions of source code must retain the above copyright notice, +// this list of conditions and the following disclaimer. +// * Redistributions in binary form must reproduce the above copyright notice, +// this list of conditions and the following disclaimer in the documentation +// and/or other materials provided with the distribution. +// * Neither the name of Google Inc. nor the names of its contributors may be +// used to endorse or promote products derived from this software without +// specific prior written permission. +// +// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" +// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE +// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE +// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE +// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR +// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF +// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS +// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN +// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) +// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE +// POSSIBILITY OF SUCH DAMAGE. +// +// Author: sameeragarwal@google.com (Sameer Agarwal) +// keir@google.m (Keir Mierle) +// +// This is the interface through which the least squares solver accesses the +// residual and Jacobian of the least squares problem. Users are expected to +// subclass CostFunction to define their own terms in the least squares problem. +// +// It is recommended that users define templated residual functors for use as +// arguments for AutoDiffCostFunction (see autodiff_cost_function.h), instead of +// directly implementing the CostFunction interface. This often results in both +// shorter code and faster execution than hand-coded derivatives. However, +// specialized cases may demand direct implementation of the lower-level +// CostFunction interface; for example, this is true when calling legacy code +// which is not templated on numeric types. + +#ifndef CERES_PUBLIC_COST_FUNCTION_H_ +#define CERES_PUBLIC_COST_FUNCTION_H_ + +#include <vector> +#include "ceres/internal/macros.h" +#include "ceres/internal/port.h" +#include "ceres/types.h" + +namespace ceres { + +// This class implements the computation of the cost (a.k.a. residual) terms as +// a function of the input (control) variables, and is the interface for users +// to describe their least squares problem to Ceres. In other words, this is the +// modelling layer between users and the Ceres optimizer. The signature of the +// function (number and sizes of input parameter blocks and number of outputs) +// is stored in parameter_block_sizes_ and num_residuals_ respectively. User +// code inheriting from this class is expected to set these two members with the +// corresponding accessors. This information will be verified by the Problem +// when added with AddResidualBlock(). +class CostFunction { + public: + CostFunction() : num_residuals_(0) {} + + virtual ~CostFunction() {} + + // Inputs: + // + // parameters is an array of pointers to arrays containing the + // various parameter blocks. parameters has the same number of + // elements as parameter_block_sizes_. Parameter blocks are in the + // same order as parameter_block_sizes_.i.e., + // + // parameters_[i] = double[parameter_block_sizes_[i]] + // + // Outputs: + // + // residuals is an array of size num_residuals_. + // + // jacobians is an array of size parameter_block_sizes_ containing + // pointers to storage for jacobian blocks corresponding to each + // parameter block. Jacobian blocks are in the same order as + // parameter_block_sizes, i.e. jacobians[i], is an + // array that contains num_residuals_* parameter_block_sizes_[i] + // elements. Each jacobian block is stored in row-major order, i.e., + // + // jacobians[i][r*parameter_block_size_[i] + c] = + // d residual[r] / d parameters[i][c] + // + // If jacobians is NULL, then no derivatives are returned; this is + // the case when computing cost only. If jacobians[i] is NULL, then + // the jacobian block corresponding to the i'th parameter block must + // not to be returned. + virtual bool Evaluate(double const* const* parameters, + double* residuals, + double** jacobians) const = 0; + + const vector<int16>& parameter_block_sizes() const { + return parameter_block_sizes_; + } + + int num_residuals() const { + return num_residuals_; + } + + protected: + vector<int16>* mutable_parameter_block_sizes() { + return ¶meter_block_sizes_; + } + + void set_num_residuals(int num_residuals) { + num_residuals_ = num_residuals; + } + + private: + // Cost function signature metadata: number of inputs & their sizes, + // number of outputs (residuals). + vector<int16> parameter_block_sizes_; + int num_residuals_; + CERES_DISALLOW_COPY_AND_ASSIGN(CostFunction); +}; + +} // namespace ceres + +#endif // CERES_PUBLIC_COST_FUNCTION_H_ |