| // Ceres Solver - A fast non-linear least squares minimizer | |
| // Copyright 2019 Google Inc. All rights reserved. | |
| // http://ceres-solver.org/ | |
| // | |
| // 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: mierle@gmail.com (Keir Mierle) | |
| namespace ceres { | |
| // Using this callback interface, Ceres can notify you when it is | |
| // about to evaluate the residuals or jacobians. With the callback, | |
| // you can share computation between residual blocks by doing the | |
| // shared computation in PrepareForEvaluation() before Ceres calls | |
| // CostFunction::Evaluate(). It also enables caching results between a | |
| // pure residual evaluation and a residual & jacobian evaluation, via | |
| // the new_evaluation_point argument. | |
| // | |
| // One use case for this callback is if the cost function compute is | |
| // moved to the GPU. In that case, the prepare call does the actual | |
| // cost function evaluation, and subsequent calls from Ceres to the | |
| // actual cost functions merely copy the results from the GPU onto the | |
| // corresponding blocks for Ceres to plug into the solver. | |
| // | |
| // NOTE: Ceres provides no mechanism to share data other than the | |
| // notification from the callback. Users must provide access to | |
| // pre-computed shared data to their cost functions behind the scenes; | |
| // this all happens without Ceres knowing. | |
| // | |
| // One approach is to put a pointer to the shared data in each cost | |
| // function (recommended) or to use a global shared variable | |
| // (discouraged; bug-prone). As far as Ceres is concerned, it is | |
| // evaluating cost functions like any other; it just so happens that | |
| // behind the scenes the cost functions reuse pre-computed data to | |
| // execute faster. | |
| class CERES_EXPORT EvaluationCallback { | |
| public: | |
| virtual ~EvaluationCallback(); | |
| // Called before Ceres requests residuals or jacobians for a given setting of | |
| // the parameters. User parameters (the double* values provided to the cost | |
| // functions) are fixed until the next call to PrepareForEvaluation(). If | |
| // new_evaluation_point == true, then this is a new point that is different | |
| // from the last evaluated point. Otherwise, it is the same point that was | |
| // evaluated previously (either jacobian or residual) and the user can use | |
| // cached results from previous evaluations. | |
| virtual void PrepareForEvaluation(bool evaluate_jacobians, | |
| bool new_evaluation_point) = 0; | |
| }; | |
| } // namespace ceres | |