modppl 0.3.1

a experimental library for probabilistic programming in Rust.
Documentation 
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use super::model::PointedBuffer;
use super::types_2d::{Bounds, Point};
use modppl::{mvnormal, ArgDiff, Distribution, GenFn, Real, Trace};
use nalgebra::DMatrix;
use rand::rngs::ThreadRng;
use std::sync::Weak;

pub struct DriftProposal {
    pub drift_cov: DMatrix<Real>,
}

pub type DriftProposalArgs = (Weak<Trace<Bounds, PointedBuffer, Point>>, ());

impl GenFn<DriftProposalArgs, PointedBuffer, ()> for DriftProposal {
    fn simulate(&self, args: DriftProposalArgs) -> Trace<DriftProposalArgs, PointedBuffer, ()> {
        let mut rng = ThreadRng::default();
        let prev_trace = args.0.upgrade().unwrap();
        let mut choices = (None, prev_trace.data.1.clone());

        let new_latent = mvnormal.random(
            &mut rng,
            (prev_trace.data.0.clone().unwrap(), self.drift_cov.clone()),
        );
        choices.0 = Some(new_latent);
        let logp = mvnormal.logpdf(
            &choices.0.clone().unwrap(),
            (prev_trace.data.0.clone().unwrap(), self.drift_cov.clone()),
        );

        Trace::new(args, choices, (), logp)
    }

    fn generate(
        &self,
        args: DriftProposalArgs,
        constraints: PointedBuffer,
    ) -> (Trace<DriftProposalArgs, PointedBuffer, ()>, Real) {
        let prev_trace = args.0.upgrade().unwrap();
        let mut choices = (None, prev_trace.data.1.clone());

        let new_latent: Point;
        let logp: Real;
        let mut weight = 0.;
        match constraints.0 {
            Some(latent_constraint) => {
                new_latent = latent_constraint;
                logp = mvnormal.logpdf(
                    &new_latent,
                    (prev_trace.data.0.clone().unwrap(), self.drift_cov.clone()),
                );
                weight = logp;
            }
            None => {
                let mut rng = ThreadRng::default();
                new_latent = mvnormal.random(
                    &mut rng,
                    (prev_trace.data.0.clone().unwrap(), self.drift_cov.clone()),
                );
                logp = mvnormal.logpdf(
                    &new_latent,
                    (prev_trace.data.0.clone().unwrap(), self.drift_cov.clone()),
                );
            }
        }
        choices.0 = Some(new_latent);

        (Trace::new(args, choices, (), logp), weight)
    }

    fn update(
        &self,
        _: Trace<DriftProposalArgs, PointedBuffer, ()>,
        _: DriftProposalArgs,
        _: ArgDiff,
        _: PointedBuffer,
    ) -> (
        Trace<DriftProposalArgs, PointedBuffer, ()>,
        PointedBuffer,
        Real,
    ) {
        panic!("not implemented")
    }
}