Model overview
UltraBERT is a family of English bidirectional encoders with a native 32K context that reach state of the art on both classification and retrieval, two task families on which previous encoders had to choose a side. UltraBERT is supported natively in `transformers >= 5.20`. On earlier 5.x versions (tested with 5.16.1), pass `trust_remote_code=True`. FlashAttention 2 is recommended for long inputs; SDPA and eager attention are also supported. We recommend starting from the settings used in the paper. For classification: AdamW (β1 0.9, β2 0.98, ε 1e-6), weight decay 0.1, a linear schedule with 5% warm-up, and a learning rate swept over {5e-6,8e-6,1e-5,3e-5,5e-5,8e-5}. For dense retrieval: mean pooling with a contrastive loss and a wider learning-rate sweep of {1e-5,3e-5,5e-5,8e-5,1e-4,2e-4,3e-4,5e-4,8e-4,1e-3}.
Key features
特点摘要待依据来源补齐，不凭模型名称推断能力。
Limitations & considerations
Sources are insufficient to establish specific limitations. Verify task performance, latency, data policies, licensing and version lifecycle.
Source prices & cost analysis
Prices vary by channel, region and configuration. Channel quotes are listed independently and are not treated as a single official provider price.
| Source / channel | Input | Output | Billing unit | Collected at |
|---|---|---|---|---|
| No verified prices yet. Check the source channel. | ||||
Estimate monthly base token costs
Estimates exclude cache discounts, tiered pricing, multimodal surcharges, web search, taxes and additional reasoning output.
Public benchmarks & run configuration
暂无已采集的可核验公开评分。模型未上榜不代表能力较低。
View full indexed rankings →Frequently asked questions
Do open weights permit free commercial use?
Not necessarily. Check the version license, commercial conditions and usage policies. Self-hosting incurs compute and maintenance costs.
Are these real-time billing prices?
These are timestamped source snapshots, not live billing prices. Check the channel for current versions, regions, discounts and billing methods.
Sources & traceability
许可证：apache-2.0。模型介绍与第三方评测均以原来源的具体版本和方法为准。