Pulsar 16B is a model based on NVIDIA-Nemotron-3-Nano-30B-A3B-BF16, developed by Multiverse Computing. The original model is a ~31.6B parameter, part of the Nemotron model family. It supports long-context inference up to 1M tokens and is designed for general-purpose language modeling tasks.
This version applies model compression techniques to significantly reduce parameter count and deployment requirements while maintaining compatibility with the Nemotron Hybrid Mamba2-Transformer with MoE architecture. The resulting model achieves 50% compression, reducing the parameter count to 16.15B parameters and lowering memory requirements.
This model can be loaded with the Transformers API. Use trust_remote_code=True. Recommended approach: AutoModelForCausalLM with apply_chat_template. This configuration has been tested with Transformers 4.57.6.
Alternatively you can use the pipeline API with trust_remote_code=True; the pipeline returns the full conversation structure, so extract the assistant message from outputs[0]["generated_text"] as needed.
vLLM Serving
Installation
pip install -U "vllm>=0.12.0"
Reasoning parser (NVIDIA)
Pulsar 16B uses the same Nemotron v3 reasoning tags as the base model. NVIDIA provides the vLLM plugin as nano_v3_reasoning_parser.py on the base Hugging Face repo (not specific to Pulsar). Direct download:
You can keep any local filename; the vllm serve flags below assume the file is in the current directory as nano_v3_reasoning_parser.py. If you mirror an identical copy under the Pulsar model repo, use that URL instead.
Note: The NeMo container nvcr.io/nvidia/nemo:25.11.nemotron_3_nano comes with mamba_ssm and causal-conv1d pre-installed.
Thinking (Reasoning) Control
Pulsar 16B supports a hybrid reasoning mode: the model can either think step-by-step before answering (reasoning mode) or reply directly (non-reasoning mode). The behaviour is controlled via the enable_thinking flag in the chat template.
When thinking is ON the model opens a <think> block before the answer.
python
1output = tokenizer.decode(outputs[0], skip_special_tokens=True)2# Split on </think> to separate reasoning from the final answer3if"</think>"in output:4 reasoning, answer = output.split("</think>",1)5 reasoning = reasoning.replace("<think>","").strip()6 answer = answer.strip()7else:8 answer = output
vLLM
Server-level default
Set the default for all requests at startup with --default-chat-template-kwargs.
--trust-request-chat-template is required to allow per-request overrides.
Individual requests can override the server default by passing chat_template_kwargs in the request body. This works regardless of the server-level default.
The base model nvidia/NVIDIA-Nemotron-3-Nano-30B-A3B-BF16 is a large language model (LLM) trained from scratch by NVIDIA, and designed as a unified model for both reasoning and non-reasoning tasks. The model's reasoning capabilities can be configured through a flag in the chat template. See the original model card for details.
CompactifAI Compression
CompactifAI was applied to produce a smaller, efficient model (16B parameters) while aiming to preserve reasoning and tool-use capabilities. Supervised Fine Tuning was applied for improving cabapilities.
Measure Window: Each phase lasts 3 minutes (excluding ramp-up and cool-down periods).
Workload shape: 8k/16k workload as in the original model's card.
Long Context
Pulsar 16B preserves strong long-context behavior after compression, tracking the Nemotron-3-Nano-30B-A3B baseline closely across retrieval-heavy and full-suite long-context evaluations. Results are reported for LongBench v1, AA-LCR, NIAH, and RULER groupings up to 256k context.
Long-context benchmark results
Benchmark
Nemotron 3 Nano 30B A3B
Pulsar 16B
Longbench
31.84
29.84
AA-LCR
33.67
29.33
NIAH (@100K)
100.00
100.00
RULER (@128K)
95.02
94.20
RULER (@256K)
92.02
87.74
Evaluation Methodology
Benchmark scores were obtained with the following setups. Methodology varies by benchmark family.
Inference:
Backend: VLLM 0.18.0
Nemotron models:temp 1.0, top_p 1.0
GPT-OSS-20B:temp: 1.0, top_p: 1.0, reasoning_effort: high