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Tim Z. Xiao

8 accepted papers

2025

Can Large Language Models Understand Symbolic Graphics Programs?

ICLR 2025spotlight

Against the backdrop of enthusiasm for large language models (LLMs), there is a growing need to scientifically assess their capabilities and shortcomings. This is nontrivial in part because it is difficult to find tasks which the models have not encountered during training. Utilizing symbolic graphi…

Cited by 11SourcePDFScholar
2025

Efficient Diversity-Preserving Diffusion Alignment via Gradient-Informed GFlowNets

ICLR 2025poster

While one commonly trains large diffusion models by collecting datasets on target downstream tasks, it is often desired to align and finetune pretrained diffusion models with some reward functions that are either designed by experts or learned from small-scale datasets. Existing post-training method…

Cited by 0SourcePDFScholar
2025

Improving Probabilistic Diffusion Models With Optimal Diagonal Covariance Matching

ICLR 2025oral

The probabilistic diffusion model has become highly effective across various domains. Typically, sampling from a diffusion model involves using a denoising distribution characterized by a Gaussian with a learned mean and either fixed or learned covariances. In this paper, we leverage the recently pr…

Cited by 0SourcePDFScholar
2025

Reparameterized LLM Training via Orthogonal Equivalence Transformation

NeurIPS 2025poster

While large language models (LLMs) are driving the rapid advancement of artificial intelligence, effectively and reliably training these large models remains one of the field's most significant challenges. To address this challenge, we propose POET, a novel reParameterized training algorithm that us…

Cited by 0SourceScholar
2025

Value Gradient Guidance for Flow Matching Alignment

NeurIPS 2025poster

While methods exist for aligning flow matching models -- a popular and effective class of generative models -- with human preferences, existing approaches fail to achieve both adaptation efficiency and probabilistically sound prior preservation. In this work, we leverage the theory of optimal contro…

Cited by 0SourceScholar
2025

Your Finetuned Large Language Model is Already a Powerful Out-of-distribution Detector

AISTATS 2025poster

We revisit the likelihood ratio between a pretrained large language model (LLM) and its finetuned variant as a criterion for out-of-distribution (OOD) detection. The intuition behind such a criterion is that, the pretrained LLM has the prior knowledge about OOD data due to its large amount of traini…

Cited by 0SourcecodeScholar
2023

Iterative Teaching by Data Hallucination

AISTATS 2023poster

We consider the problem of iterative machine teaching, where a teacher sequentially provides examples based on the status of a learner under a discrete input space (i.e., a pool of finite samples), which greatly limits the teacher’s capability. To address this issue, we study iterative teaching unde…