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Replace step function with contious scaling

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Patrick Niklaus 2018-04-21 17:26:21 +00:00 committed by Patrick Niklaus
parent 7d50e5afe0
commit 9d10503a9c
1 changed files with 27 additions and 16 deletions
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43
src/engine/routing_algorithms/alternative_path_mld.cpp
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@ -94,25 +94,36 @@ double getLongerByFactorBasedOnDuration(const EdgeWeight duration)
// We scale the weights with a step function based on some rough guestimates, so that
// they match tens of minutes, in the low hours, tens of hours, etc.
// Todo: instead of a piecewise constant function should this be a continuous function?
// At the moment there are "hard" jump edge cases when crossing the thresholds.
// Computed using a least-squares curve fitiing on the following values:
//
// def func(xs, a, b, c, d):
// return a + b/(xs-d) + c/(xs-d)**3
//
// xs = np.array([5 * 60, 10 * 60, 30 * 60, 60 * 60, 3 * 60 * 60, 10 * 60 * 60])
// ys = np.array([1.0, 0.75, 0.5, 0.3, 0.2, 0.1])
//
// xs_interp = np.arange(5*60, 10*60*60, 5*60)
// ys_interp = np.interp(xs_interp, xs, ys)
//
// params, _ = scipy.optimize.curve_fit(func, xs_interp, ys_interp)
const constexpr auto a = 9.49571282e-02;
const constexpr auto b = 1.25440191e+03;
const constexpr auto c = 2.06152165e+09;
const constexpr auto d = -1.71666881e+03;
const constexpr double DEFAULT_LONGER_BY = 0.5;
const constexpr auto minutes = 60.;
const constexpr auto hours = 60. * minutes;
if (duration < EdgeWeight(5 * 60))
{
return 1.0;
}
else if (duration > EdgeWeight(10 * 60 * 60))
{
return 0.10;
}
if (duration < EdgeWeight(10 * minutes))
return DEFAULT_LONGER_BY * 1.20;
else if (duration < EdgeWeight(30 * minutes))
return DEFAULT_LONGER_BY * 1.00;
else if (duration < EdgeWeight(1 * hours))
return DEFAULT_LONGER_BY * 0.90;
else if (duration < EdgeWeight(3 * hours))
return DEFAULT_LONGER_BY * 0.70;
else if (duration > EdgeWeight(10 * hours))
return DEFAULT_LONGER_BY * 0.50;
// Bigger than 10 minutes but smaller than 10 hours
BOOST_ASSERT(duration > 5*60 && duration < 10*60*60);
return DEFAULT_LONGER_BY;
return a + b/(duration-d) + c/std::pow(duration-d, 3);
}
Parameters getDefaultParameters()