HCNAF: Hyper-Conditioned Neural Autoregressive Flow and its Application for Probabilistic Occupancy Map Forecasting

TL;DR

HCNAF is a novel neural autoregressive flow model that accurately estimates complex conditional probability densities, demonstrating superior performance and scalability in high-dimensional tasks like self-driving data prediction.

Contribution

This paper introduces HCNAF, a new hyper-conditioned neural autoregressive flow model that enhances density estimation with large conditions and scales to complex, high-dimensional problems.

Findings

Effective density estimation on toy and MNIST datasets

Generalizes well to unseen conditions

Achieves state-of-the-art results in self-driving prediction tasks

Abstract

We introduce Hyper-Conditioned Neural Autoregressive Flow (HCNAF); a powerful universal distribution approximator designed to model arbitrarily complex conditional probability density functions. HCNAF consists of a neural-net based conditional autoregressive flow (AF) and a hyper-network that can take large conditions in non-autoregressive fashion and outputs the network parameters of the AF. Like other flow models, HCNAF performs exact likelihood inference. We conduct a number of density estimation tasks on toy experiments and MNIST to demonstrate the effectiveness and attributes of HCNAF, including its generalization capability over unseen conditions and expressivity. Finally, we show that HCNAF scales up to complex high-dimensional prediction problems of the magnitude of self-driving and that HCNAF yields a state-of-the-art performance in a public self-driving dataset.