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barthelomew

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ML research; debargha@case.edu

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AI (VLM-based) radiology models can sound confident and still be wrong ; hallucinating diagnoses that their own findings don't support. This is a silent, and dangerous failure mode.

Our new paper introduces a verification layer that checks every diagnostic claim an AI makes before it reaches a clinician. When our system says a diagnosis is supported, it's been mathematically proven - not just guessed. Every model we tested improved significantly after verification, with our best result hitting 99% soundness.

We're excited about what comes next in building verifiably correct AI systems.

Predict your distributed LLM training time before you burn GPU hours.

We've open-sourced a tool (https://github.com/DebarghaG/estimate-train-time) that estimates wall-clock time for LLM training across multi-GPU setups with 3D parallelism (pipeline, tensor, and data).

This problem is extremely hard: you're modeling the interplay of thousands of GPU kernels, NCCL collectives across heterogeneous network topologies, pipeline bubbles, activation recomputation, and ZeRO optimizer communication all while these components interact in non-obvious ways at scale. Even off-by-2x estimates are useless for capacity planning.

Two years of painstaking work, ~$100k worth of cluster time, validated on real workloads at Perlmutter (NERSC) and Vista (TACC) some of the largest HPC clusters available for open science.

How it works: 1. Kernel-level profiling: We sample execution times for kernels like Flash Attention, fused GEMM (QKV/FFN projections), RMSNorm, embedding lookups, and cross-entropy loss across the (batch, seq_len, hidden_dim, num_heads, MP degree) parameter space. 2. Communication modeling: NCCL benchmarks capture ring all-reduce (tensor/data parallel sync), all-gather (ZeRO-1 parameter collection), and P2P send/recv (pipeline stage activation transfers) across intra-node NVLink and inter-node InfiniBand topologies. 3. Analytical composition: Operator predictions feed into a pipeline scheduling model (AF-AB / 1F1B) that accounts for bubble overhead: (PP - 1) / (num_microbatches + PP - 1) idle fraction, layer distribution across head/middle/tail stages, and overlapped DP gradient sync. 4. Runs on CPU (post-sampling) no GPU access needed for inference of training time.

This is highly extensible as a recipe. You may profile your own hardware with bundled kernel-sampling and NCCL-benchmarking scripts. You can add custom operators by implementing the regressor interface.

This work builds on our HiPC 2025 paper on fine-grained GPU performance modeling. Earlier code to reproduce results in paper: https://github.com/ICICLE-ai/distributed_training_estimator_...

Looking for early adopters and feedback especially teams doing parallelism strategy search or capacity planning at scale.

Paper LaTeX files often contain surprising details. When a paper lacks code, looking at latex source has become a part of my reproduction workflow. The comments often reveal non-trivial insights. Often, they reveal a simpler version of the methodology section (which for poor "novelty" purposes is purposely obscured via mathematical jargon).

You're right about the 2023 JSON mode, but our project required enforcing a much more complex DSL grammar (look in Appendix for details), not just ensuring a *valid JSON object*. The newer structured output APIs are a significant improvement, but the earlier tools weren't a fit for the specific constraints we were working under at the time.

Yep. The paper was written last year with GPT-4o. Things have become a lot better since then with newer models.

E.g. https://arxiv.org/pdf/2505.20047 Tab 1, we compare the performance on text-only vs SMT-only. o3-mini does pretty well at mirroring its text reasoning in its SMT, vs Gemini Flash 2.0.

Illustration of this can be seen in Fig 14, 15 on Page 29.

In commercially available products like AWS Automated Reasoning Checks, you build a model from your domain (e.g. from a PDF policy document), cross verify it for correctness, and during answer generation, you only cross check whether your Q/A pairs from the LLM comply with the policy using a solver with guarantees.

This means that they can give you a 99%+ soundness guarantee, which basically means that if the service says the Q/A pair is valid or guaranteed w.r.t the policy, it is right more than 99% of the time.

https://aws.amazon.com/blogs/aws/minimize-ai-hallucinations-...

Hey there! I mostly designed and wrote most of the actual interpreter during my internship at Microsoft Research last summer. Constrained decoding for GPT-4 wasn’t available when we started designing the DSL, and besides, creating a regex to constrain this specific DSL is quite challenging.

When the grammar of the language is better defined, like SMT (https://arxiv.org/abs/2505.20047) - we are able to do this with open source LLMs.

Large Language Models (LLMs) have revolutionized natural language processing, yet they struggle with inconsistent reasoning, particularly in novel domains and complex logical sequences. This research introduces Proof of Thought, a framework that enhances the reliability and transparency of LLM outputs. Our approach bridges LLM-generated ideas with formal logic verification, employing a custom interpreter to convert LLM outputs into First Order Logic constructs for theorem prover scrutiny. Central to our method is an intermediary JSON-based Domain-Specific Language, which by design balances precise logical structures with intuitive human concepts. This hybrid representation enables both rigorous validation and accessible human comprehension of LLM reasoning processes. Key contributions include a robust type system with sort management for enhanced logical integrity, explicit representation of rules for clear distinction between factual and inferential knowledge, and a flexible architecture that allows for easy extension to various domain-specific applications. We demonstrate Proof of Thought's effectiveness through benchmarking on StrategyQA and a novel multimodal reasoning task, showing improved performance in open-ended scenarios. By providing verifiable and interpretable results, our technique addresses critical needs for AI system accountability and sets a foundation for human-in-the-loop oversight in high-stakes domains.

What a fantastic visualisation. Truly puts the staggering scale of things into perspective.

Now, imagine digital public goods such as Aadhaar and UPI being rolled out across all of these countries all at once.

Yes ofcourse, that side project I haven't touched for 3 years now obviously needs a full rewrite in the new language/framework I've been learning.

This does look very interesting. I like it.

I shall admit I've spent too much time though building my own journalling apps too. What's the right tradeoff- I wonder - between writing your own journalling apps v/s time spent journalling.

Once you start prompt-engineering, the answers, in seclusion look pretty great - and show some understanding of the domain.

Yet, if you donot do this - they end up spitting out some randomly associated phrases/answers. This is a problem when you're asking a model, a question who's answer you donot completely know. How do you trust it to give the right answer?

If you donot know the answer beforehand - you cannot prompt-engineer the model to give the "right answers".

"Expert systems" from the 80s and the 90s, were pretty good at giving the "right answers" inside a closed domain. Those were truly wonderful systems.