Static configurations. More...

#include <api.h>

Public Attributes
const char *	pot_type
	Type of potential. More...

int32_t	n_pot
	Approximation order of potential. More...

int32_t	trajectory_size
	Size of trajectory. More...

int32_t	int_steps
	Number of integration steps between trajectory points. More...

double	min_dist
	Minimal allowed distance between missiles and planets. More...

const char *	composition_scheme
	Composition method of integrator. More...

int32_t	n_stages
	Number of stages of the composition method. More...

Detailed Description

Static configurations.

There are several static configurations that can be set at compile-time. Use grvx_get_config() to get the configuration that was used during compilation. The corresponding compile-time constants that can be passed to CMake are:

GRVX_POT_TYPE: same as GrvxConfig::pot_type
GRVX_N_POT: same as GrvxConfig::n_pot
GRVX_TRAJECTORY_SIZE: same as GrvxConfig::trajectory_size
GRVX_INT_STEPS: same as GrvxConfig::int_steps
GRVX_MIN_DIST: same as GrvxConfig::min_dist
GRVX_P_MIN: same as GrvxConfig::p_min
GRVX_COMPOSITION_SCHEME: same as GrvxConfig::composition_scheme

Note that none of these settings is necessarily needed to interact with the API, for example, grvx_propagate_missile() returns the number of simulated steps stored in the trajectory sequence upon calling. In fact, it is safer to prefer this value over GrvxConfig::trajectory_size because the former also reflects cases where less values were stored in case of a collision with a planet.

Member Data Documentation

◆ composition_scheme

const char* GrvxConfig::composition_scheme

Composition method of integrator.

The composition method of the integrator encoded as "pXsY" where X is the integration order and Y is the number of stages.

◆ int_steps

int32_t GrvxConfig::int_steps

Number of integration steps between trajectory points.

Number of integration steps between consecutive points of a trajectory. Note that changing this number effectively speeds-up or slows-down the simulated and simulation time.

Possible values: Positive, non-zero integer values.

◆ min_dist

double GrvxConfig::min_dist

Minimal allowed distance between missiles and planets.

If missiles approach planets closer than this minimal distance, propagation is stopped.

Possible values: Positive floating point values.

◆ n_pot

int32_t GrvxConfig::n_pot

Approximation order of potential.

There is no closed-form for \(V_{3\mathrm{D}} = \frac{1}{4\pi} \sum_{j=0}^\infty V^{(j)}_{3\mathrm{D}}\), but the series can be treated as a perturbation expansion with \(V^{(j)}_{3\mathrm{D}} > V^{(j')}_{3\mathrm{D}}\) if \(j < j'\). Empirically, we find that

\[ V_{3\mathrm{D}} \approx \frac{1}{4\pi} \sum_{j=0}^{\texttt{n_pot}-1} V^{(j)}_{3\mathrm{D}} \]

converges fast and yields decent approximations.

For \(V_{2\mathrm{D}}\) a closed-form expression does exist and no approximation is needed.

Possible values: Positive integer values or undefined if GrvxConfig::pot_type is "2D".

◆ n_stages

int32_t GrvxConfig::n_stages

Number of stages of the composition method.

See GrvxConfig.composition_scheme for details.

◆ pot_type

const char* GrvxConfig::pot_type

Type of potential.

Currently, we support two types of potentials, \(V_{2\mathrm{D}}\) and \(V_{3\mathrm{D}}\) and identify them by the strings "2D" and "3D", respectively.

Possible values: "2D" and "3D".

◆ trajectory_size

int32_t GrvxConfig::trajectory_size

Size of trajectory.

Missiles are propagated for multiple time steps. The result is stored in arrays with trajectory_size elements. See Trajectory for more details.