quadratic_calculator.cpp
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00001 /*
00002  * Copyright (c) 2013, Willow Garage, Inc.
00003  * All rights reserved.
00004  *
00005  * Redistribution and use in source and binary forms, with or without
00006  * modification, are permitted provided that the following conditions are met:
00007  *
00008  *     * Redistributions of source code must retain the above copyright
00009  *       notice, this list of conditions and the following disclaimer.
00010  *     * Redistributions in binary form must reproduce the above copyright
00011  *       notice, this list of conditions and the following disclaimer in the
00012  *       documentation and/or other materials provided with the distribution.
00013  *     * Neither the name of the Willow Garage, Inc. nor the names of its
00014  *       contributors may be used to endorse or promote products derived from
00015  *       this software without specific prior written permission.
00016  *
00017  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
00018  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
00019  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
00020  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
00021  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
00022  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
00023  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
00024  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
00025  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
00026  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
00027  * POSSIBILITY OF SUCH DAMAGE.
00028  */
00029 
00030 #include <global_planner/quadratic_calculator.h>
00031 
00032 namespace global_planner {
00033 float QuadraticCalculator::calculatePotential(float* potential, unsigned char cost, int n, float prev_potential) {
00034     // get neighbors
00035     float u, d, l, r;
00036     l = potential[n - 1];
00037     r = potential[n + 1];
00038     u = potential[n - nx_];
00039     d = potential[n + nx_];
00040     //  ROS_INFO("[Update] c: %f  l: %f  r: %f  u: %f  d: %f\n",
00041     //     potential[n], l, r, u, d);
00042     //  ROS_INFO("[Update] cost: %d\n", costs[n]);
00043 
00044     // find lowest, and its lowest neighbor
00045     float ta, tc;
00046     if (l < r)
00047         tc = l;
00048     else
00049         tc = r;
00050     if (u < d)
00051         ta = u;
00052     else
00053         ta = d;
00054 
00055     float hf = cost; // traversability factor
00056     float dc = tc - ta;        // relative cost between ta,tc
00057     if (dc < 0)         // tc is lowest
00058             {
00059         dc = -dc;
00060         ta = tc;
00061     }
00062 
00063     // calculate new potential
00064     if (dc >= hf)        // if too large, use ta-only update
00065         return ta + hf;
00066     else            // two-neighbor interpolation update
00067     {
00068         // use quadratic approximation
00069         // might speed this up through table lookup, but still have to
00070         //   do the divide
00071         float d = dc / hf;
00072         float v = -0.2301 * d * d + 0.5307 * d + 0.7040;
00073         return ta + hf * v;
00074     }
00075 }
00076 }
00077 


global_planner
Author(s): David Lu!!
autogenerated on Sun Mar 3 2019 03:46:53