ssapy.rvsampler

This module provides functions and classes for orbital mechanics calculations, optimization techniques, sampling methods, and orbital parameter translations.

Functions

circular_guess(arc[, indices])	Guess position and velocity from two closely spaced (in time) observations of ra/dec.
damper(chi, damp)	Pseudo-Huber loss function.
damper_deriv(chi, damp[, derivnum])	Derivative of the pseudo-Huber loss function.
eq2kep(eq)	Convert equinoctial orbital elements to classical Keplerian orbital elements.
sample_ball(p0, std[, nSample])	Produce a ball of walkers around an initial parameter value.

Classes

APrior(amean, asigma)	Gaussian prior on orbit semimajor axis a.
AreaPrior([mean, sigma])	Gaussian prior on log10(area) of object.
DirectInitializer(samples[, replace])	Directly specify initial position and velocity samples.
DistanceProjectionInitializer(arc, rho[, ...])	Initialize position and velocity from two closely spaced (in time) observations of ra/dec.
EPrior(emean, esigma)	Gaussian prior on orbit eccentricity e.
EmceeSampler(probfn, initializer[, nWalker])	A sampler built on the emcee package.
EquinoctialExEyPrior(sigma)	Gaussian prior on equinoctial ex and ey, favoring ex = ey = 0.
EquinoctialLMOptimizer(probfn, initel[, ...])	Optimizer that employs Levenberg-Marquardt least-squares fitting and fits in Kozai mean Keplerian element space.
GEOProjectionInitializer(arc[, rSigma, vSigma])	Initialize position and velocity samples by projecting an observed ra/dec into the equatorial plane and assuming a GEO statationary orbital velocity.
GaussianRVInitializer(rMean, vMean[, ...])	Generate position and velocity samples as an isotropic Gaussian distribution around an asserted position and velocity.
LMOptimizer(probfn, initRV[, fracstep, ...])	Optimizer that employs Levenberg-Marquardt least-squares fitting.
LMOptimizerAngular(probfn, initGuess, ...[, ...])	Optimizer that employs Levenberg-Marquardt least-squares fitting.
LeastSquaresOptimizer(probfn, initparam, ...)	Base class for LeastSquaresOptimizers
Log10AreaPrior([mean, sigma])	Gaussian prior on log10(area) of object.
MHSampler(probfn, initializer, proposer, nChain)	Generate MCMC samples using a Metropolis-Hastings sampler.
MVNormalProposal(cov)	A multivariate normal proposal distribution.
ParamOrbitAngle(initparam, epoch, ...)	Translate between angle-based orbital parameters and orbit objects.
ParamOrbitEquinoctial(*args, **kwargs)	Translate between equinoctial parameters and orbit objects.
ParamOrbitRV(*args, **kwargs)	Translate between position-velocity parameters and orbit objects.
ParamOrbitTranslator(initparam, epoch[, ...])	Class for making parameters into Orbits and vice-versa.
RPrior(rmean, rsigma)	Gaussian prior on distance from origin |r|.
RVProbability(arc, epoch[, priors, ...])	A class to manage MCMC sampling of orbits (parameterized by position and velocity at a given epoch) given some angular observations.
RVSigmaProposal(rSigma, vSigma)	Isotropic multivariate normal proposal distribution.
SGP4LMOptimizer(probfn, initel[, fracstep, ...])	Optimizer that employs Levenberg-Marquardt least-squares fitting and fits in Kozai mean Keplerian element space.
VPrior(vmean, vsigma)	Gaussian prior on velocity magnitude |v|.

Class Inheritance Diagram