chomp_cost.cpp
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00034 
00035 /* Author: Mrinal Kalakrishnan */
00036 
00037 #include <chomp_motion_planner/chomp_cost.h>
00038 #include <chomp_motion_planner/chomp_utils.h>
00039 #include <eigen3/Eigen/LU>
00040 
00041 using namespace Eigen;
00042 using namespace std;
00043 
00044 namespace chomp
00045 {
00046 
00047 ChompCost::ChompCost(const ChompTrajectory& trajectory, int joint_number, const std::vector<double>& derivative_costs, double ridge_factor)
00048 {
00049   int num_vars_all = trajectory.getNumPoints();
00050   int num_vars_free = num_vars_all - 2*(DIFF_RULE_LENGTH-1);
00051   MatrixXd diff_matrix = MatrixXd::Zero(num_vars_all, num_vars_all);
00052   quad_cost_full_ = MatrixXd::Zero(num_vars_all, num_vars_all);
00053 
00054   // construct the quad cost for all variables, as a sum of squared differentiation matrices
00055   double multiplier = 1.0;
00056   for (unsigned int i=0; i<derivative_costs.size(); i++)
00057   {
00058     multiplier *= trajectory.getDiscretization();
00059     diff_matrix = getDiffMatrix(num_vars_all, &DIFF_RULES[i][0]);
00060     quad_cost_full_ += (derivative_costs[i] * multiplier) *
00061         (diff_matrix.transpose()*diff_matrix);
00062   }
00063   quad_cost_full_ += MatrixXd::Identity(num_vars_all, num_vars_all)*ridge_factor;
00064 
00065   // extract the quad cost just for the free variables:
00066   quad_cost_ = quad_cost_full_.block(DIFF_RULE_LENGTH-1, DIFF_RULE_LENGTH-1,
00067       num_vars_free, num_vars_free);
00068 
00069   // invert the matrix:
00070   quad_cost_inv_ = quad_cost_.inverse();
00071 
00072   //cout << quad_cost_inv_ << endl;
00073 
00074 }
00075 
00076 Eigen::MatrixXd ChompCost::getDiffMatrix(int size, const double* diff_rule) const
00077 {
00078   MatrixXd matrix = MatrixXd::Zero(size,size);
00079   for (int i=0; i<size; i++)
00080   {
00081     for (int j=-DIFF_RULE_LENGTH/2; j<=DIFF_RULE_LENGTH/2; j++)
00082     {
00083       int index = i+j;
00084       if (index < 0)
00085         continue;
00086       if (index >= size)
00087         continue;
00088       matrix(i,index) = diff_rule[j+DIFF_RULE_LENGTH/2];
00089     }
00090   }
00091   return matrix;
00092 }
00093 
00094 double ChompCost::getMaxQuadCostInvValue() const
00095 {
00096   return quad_cost_inv_.maxCoeff();
00097 }
00098 
00099 void ChompCost::scale(double scale)
00100 {
00101   double inv_scale = 1.0/scale;
00102   quad_cost_inv_ *= inv_scale;
00103   quad_cost_ *= scale;
00104   quad_cost_full_ *= scale;
00105 }
00106 
00107 ChompCost::~ChompCost()
00108 {
00109 }
00110 
00111 }


chomp_motion_planner
Author(s): Gil Jones
autogenerated on Wed Sep 16 2015 04:42:45