Hi, I'm Prithvi

CTO of Zetta , building energy-efficient chips for scientific computing! Based in San Francisco, originally from north-west UK.

Building towards AI that's



Design Philosophies

I don't subscribe to perceptrons and pure scaling! Respect to the giants, but the principles below are how I'm pursuing my 5 requirements! They've shaped the hardware bets at Zetta and they will remain at the heat death of the final Delaware C-corp. Statistics victorious.

Representation first

Attention encodes very little inductive bias! Its weights are entirely data-driven. Flexible when abundant data is available, but it's wrong (all models are - George Box), and it fails on datasets where samples are limited or relationships lie on a complex manifold.

Bespoke models with stronger inductive biases are better in terms of:

  • Training efficiency
  • Generalisation
  • Explainability
  • Accuracy
  • Sample/data efficiency

There is a better representation for natural language too, (it's a PDE system), we just don't know what it is yet, and that's a question that needs asking.

Darcy Flow

github ↗
MLP + CNN prediction on Darcy flow
MLP + CNN. 5,982,121 params
KAN + CNN prediction on Darcy flow
KAN + CNN. 35,919 params + wavelet bias
MLP + FNO prediction on Darcy flow
MLP + FNO. 4,667,665 params + PDE bias

Viscoplastic Materials

github ↗
Transformer prediction on viscoplastic stress field
Transformer. 4,209,205 parameters
RNO prediction on viscoplastic stress field
RNO. 52 parameters + PDE/time-series bias

Intelligence is Hierarchical

Real intelligence is hierarchical. Low-level, dumb control is handled by simple circuits in the central nervous system, (central pattern generators, CPGs). These make use of physical structure to handle unconscious, rhythmic signals for walking, flying, and swimming gaits, while freeing up the brain for higher-level control and decision making.

CPGs are quick to recover their oscillatory gaits with little feedback. They're:

  • analytically simple to design, tune, and implement
  • equipped with robust transfer characteristics
  • utterly inexpensive compared to optimisation-based or data-driven control

People are quick to default to fancy algorithms for everything, but the best engineers will always be looking for mechanical, analogue, or physically-informed solutions for their simplicity, reliability, and cost-effectiveness. Good mechanics can compensate for bad software. Good software will never be able to compensate for bad mechanics.

Neuromorphic Robots

poster ↗ github ↗
Quadrupedal robots using CPG locomotion
Spiking neuron

Reasoning under uncertainty

All models are wrong. While there are cults arising in service of algorithms, the engineers know that data is where magic manifests! Uncertainty quantification is how engineers compensate where our data-driven methods fail, since we can't afford to be wrong.

Epistemic uncertainty is used to guide where we prioritise drug synthesis, experimentation, and risk assessments. Mistakes are expensive and unnecessary. Another example is a self-driving car that's 99% accurate. It still gets 1 in 100 decisions wrong. This could happen at a school crossing, and that last 1% is where uncertainty quantification saves lives.

Drug Solubility Fitting on AqSolDB

github ↗
Active learning with Gaussian Processes

Question the default

Diffusion models add noise until the distribution is flat, then learn to denoise. The forward process is an isotropic SDE, it doesn't preserve the structure of your target. Prior information about modes and geometry is gone by construction.

Annealing is an underexplored alternative. I propose using it to improve multimodal sampling for EBMs. High temperature MCMC chains explore global landscapes, colder ones resolve local structure, and global exchange passes information between them. The prior stays entirely intact, you're just smoothening the posterior energy landscape.

In KAEM, annealing is only applied during training. Power posteriors temper from prior to full posterior, and the thermodynamic criterion decomposes the true marginal likelihood across temperatures.

  • No amortisation gap
  • No variational bound
  • Just MCMC on a low-dimensional latent space, (where it's actually viable/affordable)

At inference time, the learned prior is sampled exactly via inverse transform, no annealing or MCMC involved. Diffusion pays its sequential cost at every generation, this pays it solely during training and scales in parallel with temperatures.

Parallel Tempering

github ↗
Parallel tempering exploring a non-convex energy landscape

Numeric extremism

Having spoken to many knowledgeable and passionate people, there's a clear split in what next gen infrastructure should optimise for:

  • Model compression, quantisation, tokens/s for LLM serving and inference providers
  • High precision/stability, high order differentiability, versatility for science and engineering

While it's tempting as a hardware company to just platform low-cost inference alone, there is a rich and long history of real analysis needed for engineering and the type of intelligence I'm building. I'm not sure much of it holds without floating point representation, and I will never bow to trade-offs and mutual exclusivity.

Ozaki scheme II recovers FP64 accuracy from INT8/FP16 by decomposing floats, running the matmuls in smaller precisions, then reconstructing with the Chinese Remainder Theorem. INT8 MACs are 16x smaller than FP64; same die area -> 16x more compute. This pipelines, fuses, and avoids kernel launch slowdowns on Zetta hardware.

  • fp-emulation — recovering high precision gradient quality from low precision hardware for stable, high-order differentiation in PINN training
  • tensor_inv — matrix decompositions (LU, Cholesky, RSVD) on cheap fixed-point systolic arrays with scalar units and VPUs
  • smelt — pure integer ops for LLMs (ternary quantisation + bit-shift only activations) on commodity CPUs or cheap int hardware

Please reach out if you need ML/high-perf hardware! Especially if your workloads involve:

Would love to hear about what you're doing :)