1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
|
/* -------------------------------------------------------------------------- *
* Simbody(tm): SimTKmath *
* -------------------------------------------------------------------------- *
* This is part of the SimTK biosimulation toolkit originating from *
* Simbios, the NIH National Center for Physics-Based Simulation of *
* Biological Structures at Stanford, funded under the NIH Roadmap for *
* Medical Research, grant U54 GM072970. See https://simtk.org/home/simbody. *
* *
* Portions copyright (c) 2006-12 Stanford University and the Authors. *
* Authors: Michael Sherman, Peter Eastman *
* Contributors: *
* *
* Licensed under the Apache License, Version 2.0 (the "License"); you may *
* not use this file except in compliance with the License. You may obtain a *
* copy of the License at http://www.apache.org/licenses/LICENSE-2.0. *
* *
* Unless required by applicable law or agreed to in writing, software *
* distributed under the License is distributed on an "AS IS" BASIS, *
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. *
* See the License for the specific language governing permissions and *
* limitations under the License. *
* -------------------------------------------------------------------------- */
#include "SimTKmath.h"
#include "PendulumSystem.h"
#define ASSERT(cond) {SimTK_ASSERT_ALWAYS(cond, "Assertion failed");}
using namespace SimTK;
using std::printf;
using std::cout;
using std::endl;
class ZeroVelocityHandler : public TriggeredEventHandler {
public:
static int eventCount;
static Real lastEventTime;
ZeroVelocityHandler(PendulumSystem& pendulum) : TriggeredEventHandler(Stage::Velocity), pendulum(pendulum) {
getTriggerInfo().setTriggerOnFallingSignTransition(false);
}
Real getValue(const State& state) const override {
return state.getU(pendulum.getGuts().getSubsysIndex())[0];
}
void handleEvent(State& state, Real accuracy, bool& shouldTerminate) const override {
// This should be triggered when the pendulum reaches its farthest point in the
// negative direction: q == -1, u == 0.
Real q = state.getQ(pendulum.getGuts().getSubsysIndex())[0];
Real u = state.getU(pendulum.getGuts().getSubsysIndex())[0];
ASSERT(std::abs(q+1.0) < 0.05);
ASSERT(std::abs(u) < 0.01);
ASSERT(state.getTime() > lastEventTime);
eventCount++;
lastEventTime = state.getTime();
}
private:
PendulumSystem& pendulum;
};
class PeriodicHandler : public ScheduledEventHandler {
public:
static int eventCount;
static Real lastEventTime;
Real getNextEventTime(const State&, bool includeCurrentTime) const override {
return lastEventTime+1.5;
}
void handleEvent(State& state, Real accuracy, bool& shouldTerminate) const override {
// This should be triggered every 1.5 time units.
ASSERT(state.getTime() == lastEventTime+1.5);
eventCount++;
lastEventTime = state.getTime();
}
};
class ZeroPositionReporter : public TriggeredEventReporter {
public:
static int eventCount;
static Real lastEventTime;
ZeroPositionReporter(PendulumSystem& pendulum) : TriggeredEventReporter(Stage::Velocity), pendulum(pendulum) {
}
Real getValue(const State& state) const override {
return state.getQ(pendulum.getGuts().getSubsysIndex())[0];
}
void handleEvent(const State& state) const override {
// This should be triggered when the pendulum crosses q == 0.
Real q = state.getQ(pendulum.getGuts().getSubsysIndex())[0];
ASSERT(std::abs(q) < 0.01);
ASSERT(state.getTime() > lastEventTime);
eventCount++;
lastEventTime = state.getTime();
}
private:
PendulumSystem& pendulum;
};
class PeriodicReporter : public ScheduledEventReporter {
public:
static int eventCount;
static Real lastEventTime;
Real getNextEventTime(const State&, bool includeCurrentTime) const override {
return lastEventTime*2;
}
void handleEvent(const State& state) const override {
// This should be triggered every 1.5 time units.
ASSERT(state.getTime() == lastEventTime*2);
eventCount++;
lastEventTime = state.getTime();
}
};
int ZeroVelocityHandler::eventCount = 0;
Real ZeroVelocityHandler::lastEventTime = 0.0;
int PeriodicHandler::eventCount = 0;
Real PeriodicHandler::lastEventTime = 0.0;
int ZeroPositionReporter::eventCount = 0;
Real ZeroPositionReporter::lastEventTime = 0.0;
int PeriodicReporter::eventCount = 0;
Real PeriodicReporter::lastEventTime = 0.5;
int main () {
try {
PendulumSystem sys;
sys.addEventHandler(new ZeroVelocityHandler(sys));
sys.addEventHandler(new PeriodicHandler());
sys.addEventReporter(new ZeroPositionReporter(sys));
sys.addEventReporter(new PeriodicReporter());
sys.realizeTopology();
RungeKuttaMersonIntegrator integ(sys);
const Real t0=0;
const Real qi[] = {1,0}; // (x,y)=(1,0)
const Real ui[] = {0,0}; // v=0
const Vector q0(2, qi);
const Vector u0(2, ui);
sys.setDefaultMass(10);
sys.setDefaultTimeAndState(t0, q0, u0);
integ.setAccuracy(1e-2);
integ.setConstraintTolerance(1e-4);
const Real tFinal = 20.003;
const Real hReport = 1.;
integ.setFinalTime(tFinal);
TimeStepper ts(sys);
ts.setIntegrator(integ);
ts.initialize(sys.getDefaultState());
ASSERT(ts.getTime() == 0.0);
ts.stepTo(10.0);
ASSERT(ts.getTime() == 10.0);
ts.stepTo(50.0);
ASSERT(ts.getTime() == tFinal);
ASSERT(integ.getTerminationReason() == Integrator::ReachedFinalTime);
ASSERT(ZeroVelocityHandler::eventCount >= 10);
ASSERT(PeriodicHandler::eventCount == (int) (ts.getTime()/1.5));
ASSERT(ZeroPositionReporter::eventCount > 10);
ASSERT(PeriodicReporter::eventCount == (int) (std::log(ts.getTime())/std::log(2.0))+1);
cout << "Done" << endl;
return 0;
}
catch (std::exception& e) {
std::printf("FAILED: %s\n", e.what());
return 1;
}
}
|
