distribution/production_surface.h

Line	Exec	Source
1		/// @file
2		/// @brief The crater density of a surface of a given age: a production function times a chronology.
3		#pragma once
4
5		#include "terraingen/distribution/size_frequency.h"
6
7		#include <functional>
8		#include <memory>
9
10		namespace terraingen {
11
12		/// N(>=1 km) per m^2 on a surface `ageGyr` old, such as `NeukumLunarChronology`.
13		using Chronology = std::function<double(double ageGyr)>;
14
15		/// The cumulative crater density on a surface of a given age: a production function scaled
16		/// so that N(>=1 km) follows a chronology, N(D, T) = Phi(D) * N1(T) / Phi(1 km).
17		///
18		/// This is the population with no erosion; small craters exceed equilibrium on old surfaces.
19		class ProductionSurface final : public SizeFrequencyDistribution {
20		public:
21		/// The surface `ageGyr` Gyr old.
22		/// @param production A `ProductionRate` distribution defined at 1 km. The surface takes its
23		/// valid range and extrapolation setting.
24		/// @param chronology N(>=1 km) per m^2 for the age, which may reject ages out of its range.
25		/// @throws std::invalid_argument if `production` is null or not a production rate, or
26		/// `chronology` is empty.
27		/// @throws std::domain_error if the age is out of range or `production` is not defined at 1 km.
28		ProductionSurface(std::shared_ptr<const SizeFrequencyDistribution> production, double ageGyr,
29		const Chronology& chronology);
30
31		/// The `ProductionRate` distribution the surface scales.
32	2	const SizeFrequencyDistribution& Production() const {
33	2	return *production_;
34		}
35
36		/// The surface age in Gyr.
37	2	double AgeGyr() const {
38	2	return ageGyr_;
39		}
40
41		protected:
42		double CumulativeAt(double diameter) const override;
43		double IncrementalAt(double diameter) const override;
44		double InvertCumulative(double target, double dMin, double dMax) const override;
45
46		private:
47		std::shared_ptr<const SizeFrequencyDistribution> production_;
48		double ageGyr_;
49		double scale_;
50		};
51
52		} // namespace terraingen
53

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