Self-Adversarially Learned Bayesian Sampling

Scalable Bayesian sampling is playing an important role in modern machine learning, especially in the fast-developed unsupervised-(deep)-learning models. While tremendous progresses have been achieved via scalable Bayesian sampling such as stochastic gradient MCMC (SG-MCMC) and Stein variational gradient descent (SVGD), the generated samples are typically highly correlated. Moreover, their sample-generation processes are often criticized to be inefficient. In this paper, we propose a novel self-adversarial learning framework that automatically learns a conditional generator to mimic the behavior of a Markov kernel (transition kernel). High-quality samples can be efficiently generated by direct forward passes though a learned generator. Most importantly, the learning process adopts a self-learning paradigm, requiring no information on existing Markov kernels, e.g., knowledge of how to draw samples from them. Specifically, our framework learns to use current samples, either from the generator or pre-provided training data, to update the generator such that the generated samples progressively approach a target distribution, thus it is called self-learning. Experiments on both synthetic and real datasets verify advantages of our framework, outperforming related methods in terms of both sampling efficiency and sample quality.Comment: AAAI 201

On the photofragmentation of SF2+_2^+: Experimental evidence for a predissociation channel

We report on the first observation of the photofragmentation dynamics of SF$_2^+$. With the aid of state-of-the-art ab initio calculations on the low-lying excited cationic states of SF$_2^+$ performed by Lee et al. [J. Chem. Phys. 125, 104304 (2006)], a predissociation channel of SF$_2^+$ is evidenced by means of resonance-enhanced multilphoton ionization spectroscopy. This work represents a second experimental investigation on the low-lying excited cationic states of SF$_2^+$. [The first one is the He I photoelectron spectrum of SF$_2^+$ reported by de Leeuw et al. three decades ago, see Chem. Phys. 34, 287 (1978).]Comment: 7 pages, 3 figures, submitted to JCP as a Not