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Merge pull request #442 from JoePfeiffer/fix-getAverageThrust

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Fix getAverageThrust (fixes issue #441)
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Wes Cravens 2018-09-29 14:56:28 -05:00 committed by GitHub
commit 7177ca422c
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1 changed files with 14 additions and 17 deletions
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27
core/src/net/sf/openrocket/motor/ThrustCurveMotor.java
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@ -313,34 +313,31 @@ public class ThrustCurveMotor implements Motor, Comparable<ThrustCurveMotor>, Se
if ( endTime <= time[timeIndex+1] ) { if ( endTime <= time[timeIndex+1] ) {
// we are completely within this time slice so the computation of the average is pretty easy: // we are completely within this time slice so the computation of the average is pretty easy:
double avgImpulse = MathUtil.map(startTime, time[timeIndex], time[timeIndex+1], thrust[timeIndex], thrust[timeIndex+1]); double startThrust = MathUtil.map(startTime, time[timeIndex], time[timeIndex+1], thrust[timeIndex], thrust[timeIndex+1]);
avgImpulse += MathUtil.map(endTime, time[timeIndex], time[timeIndex+1], thrust[timeIndex], thrust[timeIndex+1]); double endThrust = MathUtil.map(endTime, time[timeIndex], time[timeIndex+1], thrust[timeIndex], thrust[timeIndex+1]);
avgImpulse /= 2.0; return (startThrust + endThrust) / 2.0;
return avgImpulse;
} }
// portion from startTime through time[timeIndex] double impulse = 0.0;
double avgImpulse = 0.0;
// For numeric stability. // portion from startTime through time[timeIndex+1]
if( time[timeIndex+1] - startTime > 0.001 ) { double startThrust = MathUtil.map(startTime, time[timeIndex], time[timeIndex+1], thrust[timeIndex], thrust[timeIndex+1]);
avgImpulse = (MathUtil.map(startTime, time[timeIndex], time[timeIndex+1], thrust[timeIndex], thrust[timeIndex+1]) + thrust[timeIndex+1]) impulse = (time[timeIndex+1] - startTime) * (startThrust + thrust[timeIndex+1]) / 2.0;
/ 2.0 * (time[timeIndex+1] - startTime);
}
// Now add the whole steps; // Now add the whole steps;
timeIndex++; timeIndex++;
while ( timeIndex < time.length -1 && endTime >= time[timeIndex+1] ) { while ( timeIndex < time.length -1 && endTime >= time[timeIndex+1] ) {
avgImpulse += (thrust[timeIndex] + thrust[timeIndex+1]) / 2.0 * (time[timeIndex+1]-time[timeIndex]); impulse += (time[timeIndex+1] - time[timeIndex]) * (thrust[timeIndex] + thrust[timeIndex+1]) / 2.0;
timeIndex++; timeIndex++;
} }
// Now add the bit after the last time index // Now add the bit after the last time index
if ( timeIndex < time.length -1 ) { if ( timeIndex < time.length -1 ) {
double endInstImpulse = MathUtil.map( endTime, time[timeIndex], time[timeIndex+1], thrust[timeIndex], thrust[timeIndex+1]); double endThrust = MathUtil.map( endTime, time[timeIndex], time[timeIndex+1], thrust[timeIndex], thrust[timeIndex+1]);
avgImpulse += (thrust[timeIndex] + endInstImpulse) / 2.0 * (endTime - time[timeIndex]); impulse += (endTime - time[timeIndex]) * (thrust[timeIndex] + endThrust) / 2.0;
} }
return avgImpulse / (endTime - startTime); return impulse / (endTime - startTime);
} }
@Override @Override