| // 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 |
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| // POSSIBILITY OF SUCH DAMAGE. |
| // |
| // Author: mierle@gmail.com (Keir Mierle) |
| |
| #ifndef CERES_PUBLIC_EVALUATION_CALLBACK_H_ |
| #define CERES_PUBLIC_EVALUATION_CALLBACK_H_ |
| |
| #include "ceres/internal/port.h" |
| |
| 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 |
| |
| #endif // CERES_PUBLIC_EVALUATION_CALLBACK_H_ |