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Indoor/grid/walk/GridWalkRandomHeadingUpdateAdv.h
2018-10-25 11:50:12 +02:00

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/*
* © Copyright 2014 Urheberrechtshinweis
* Alle Rechte vorbehalten / All Rights Reserved
*
* Programmcode ist urheberrechtlich geschuetzt.
* Das Urheberrecht liegt, soweit nicht ausdruecklich anders gekennzeichnet, bei Frank Ebner.
* Keine Verwendung ohne explizite Genehmigung.
* (vgl. § 106 ff UrhG / § 97 UrhG)
*/
#ifndef GRIDWALKRANDOMHEADINGUPDATEADV_H
#define GRIDWALKRANDOMHEADINGUPDATEADV_H
#include "../../geo/Heading.h"
#include "../Grid.h"
#include "../../math/DrawList.h"
#include "../../math/Distributions.h"
#include "../../nav/dijkstra/Dijkstra.h"
#include "../../math/Random.h"
#include "GridWalk.h"
#include "GridWalkState.h"
#include "GridWalkHelper.h"
/**
* for every walked edge: slightly update (scatter) the current heading
* pick the edge (neighbor) best matching the current heading
* if this neighbor's heading highly differs from the requested heading: start over
*
* PROs
* - simple
* - fixes the issues of GridWalkRandomHeadingUpdate by incorporating floor information
* - adds additional randomness which should be more stable
*
*/
template <typename T> class GridWalkRandomHeadingUpdateAdv : public GridWalk<T> {
friend class GridWalkHelper;
private:
/** per-edge: change heading with this sigma */
static constexpr float HEADING_CHANGE_SIGMA = Angle::degToRad(10);
/** fast random-number-generator */
Random::RandomGenerator gen;
/** 0-mean normal distribution */
std::normal_distribution<float> headingChangeDist = std::normal_distribution<float>(0.0, HEADING_CHANGE_SIGMA);
public:
/** ctor */
GridWalkRandomHeadingUpdateAdv() {
;
}
GridWalkState<T> getDestination(Grid<T>& grid, const GridWalkState<T>& start, const float distance_m) override {
return GridWalkHelper::retryOrInvert(*this, 2, grid, start, distance_m);
}
private:
// NOTE: allocate >>ONCE<<! otherwise random numbers will NOT work!
DrawList<T*> drawer;
GridWalkState<T> walk(Grid<T>& grid, const GridWalkState<T>& cur, float distRest_m, float headChange = -1) {
drawer.reset();
// create a copy (to keep heading and walked distance)
GridWalkState<T> next = cur;
// change the heading at the beginning of each walk
if (headChange == -1) {headChange = headingChangeDist(gen);}
// get a new random heading
next.heading = cur.heading + headChange;
// weight all neighbors based on this heading
for (T& neighbor : grid.neighbors(*cur.node)) {
// get the heading between the current node and its neighbor
const Heading potentialHeading = GridWalkHelper::getHeading(*cur.node, neighbor);
// calculate the difference from the requested heading
const float diffRad = potentialHeading.getDiffHalfRAD(cur.heading);
// weight this change
const float prob1 = Distribution::Normal<float>::getProbability(0, Angle::degToRad(40), diffRad);
// add the node's importance factor into the calculation
//const float prob2 = Distribution::Logistic<float>::getCDF(neighbor.imp, 1.0, 0.05);
const float prob2 = std::pow(neighbor.imp, 10);
// final importance
const float prob = prob1 * prob2;
// add for drawing
drawer.add(&neighbor, prob);
}
// all neighbors are unlikely? -> start over
if (drawer.getCumProbability() < 0.01) {return GridWalkState<T>();}
// pick the neighbor best matching this new heading
next.node = drawer.get();
// // if the best matching neighbor is far of this requested heading
// // (e.g. no good neighbor due to walls) cancel the walk. to force a retry
// const float diff = GridWalkHelper::getHeading(*cur.node, *next.node).getDiffHalfRAD(next.heading);
// if (diff > Angle::degToRad(45)) {
// return GridWalkState<T>();
// }
// get the distance up to this neighbor
const float walked_m = next.node->getDistanceInMeter(*cur.node);
distRest_m -= walked_m;
// update the heading-change and walked-distance
next.headingChange_rad += next.heading.getRAD() - cur.heading.getRAD();
next.distanceWalked_m += walked_m;
// done?
if (distRest_m <= 0) {return next;}
// another round..
return walk(grid, next, distRest_m, headChange);
}
};
#endif // GRIDWALKRANDOMHEADINGUPDATEADV_H