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00001 /********************************************************************* 00002 * Software License Agreement (BSD License) 00003 * 00004 * Copyright (c) 2009, Willow Garage, Inc. 00005 * All rights reserved. 00006 * 00007 * Redistribution and use in source and binary forms, with or without 00008 * modification, are permitted provided that the following conditions 00009 * are met: 00010 * 00011 * * Redistributions of source code must retain the above copyright 00012 * notice, this list of conditions and the following disclaimer. 00013 * * Redistributions in binary form must reproduce the above 00014 * copyright notice, this list of conditions and the following 00015 * disclaimer in the documentation and/or other materials provided 00016 * with the distribution. 00017 * * Neither the name of the Willow Garage nor the names of its 00018 * contributors may be used to endorse or promote products derived 00019 * from this software without specific prior written permission. 00020 * 00021 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 00022 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 00023 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 00024 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 00025 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 00026 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 00027 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 00028 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER 00029 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 00030 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN 00031 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 00032 * POSSIBILITY OF SUCH DAMAGE. 00033 *********************************************************************/ 00034 00037 #ifndef MULTIVARIATE_GAUSSIAN_H_ 00038 #define MULTIVARIATE_GAUSSIAN_H_ 00039 00040 #include <eigen3/Eigen/Core> 00041 #include <eigen3/Eigen/Cholesky> 00042 #include <boost/random/variate_generator.hpp> 00043 #include <boost/random/normal_distribution.hpp> 00044 #include <boost/random/mersenne_twister.hpp> 00045 #include <cstdlib> 00046 00047 namespace chomp 00048 { 00049 00053 class MultivariateGaussian 00054 { 00055 public: 00056 template <typename Derived1, typename Derived2> 00057 MultivariateGaussian(const Eigen::MatrixBase<Derived1>& mean, const Eigen::MatrixBase<Derived2>& covariance); 00058 00059 template <typename Derived> 00060 void sample(Eigen::MatrixBase<Derived>& output); 00061 00062 private: 00063 Eigen::VectorXd mean_; 00064 Eigen::MatrixXd covariance_; 00065 Eigen::MatrixXd covariance_cholesky_; 00067 int size_; 00068 boost::mt19937 rng_; 00069 boost::normal_distribution<> normal_dist_; 00070 boost::variate_generator<boost::mt19937, boost::normal_distribution<> > gaussian_; 00071 }; 00072 00074 00075 template <typename Derived1, typename Derived2> 00076 MultivariateGaussian::MultivariateGaussian(const Eigen::MatrixBase<Derived1>& mean, const Eigen::MatrixBase<Derived2>& covariance): 00077 mean_(mean), 00078 covariance_(covariance), 00079 covariance_cholesky_(covariance_.llt().matrixL()), 00080 normal_dist_(0.0,1.0), 00081 gaussian_(rng_, normal_dist_) 00082 { 00083 rng_.seed(rand()); 00084 size_ = mean.rows(); 00085 } 00086 00087 template <typename Derived> 00088 void MultivariateGaussian::sample(Eigen::MatrixBase<Derived>& output) 00089 { 00090 for (int i=0; i<size_; ++i) 00091 output(i) = gaussian_(); 00092 output = mean_ + covariance_cholesky_*output; 00093 } 00094 00095 } 00096 00097 #endif /* MULTIVARIATE_GAUSSIAN_H_ */