# candle
[](https://discord.gg/hugging-face-879548962464493619)
[](https://crates.io/crates/candle-core)
[](https://docs.rs/candle-core)
Candle is a minimalist ML framework for Rust with a focus on performance (including GPU support)
and ease of use. Try our online demos:
[whisper](https://huggingface.co/spaces/lmz/candle-whisper),
[LLaMA2](https://huggingface.co/spaces/lmz/candle-llama2),
[T5](https://huggingface.co/spaces/radames/Candle-T5-Generation-Wasm),
[yolo](https://huggingface.co/spaces/lmz/candle-yolo),
[Segment
Anything](https://huggingface.co/spaces/radames/candle-segment-anything-wasm).
## Get started
Make sure that you have [`candle-core`](https://github.com/huggingface/candle/tree/main/candle-core) correctly installed as described in [**Installation**](https://huggingface.github.io/candle/guide/installation.html).
Let's see how to run a simple matrix multiplication.
Write the following to your `myapp/src/main.rs` file:
```rust
use candle_core::{Device, Tensor};
fn main() -> Result<(), Box<dyn std::error::Error>> {
let device = Device::Cpu;
let a = Tensor::randn(0f32, 1., (2, 3), &device)?;
let b = Tensor::randn(0f32, 1., (3, 4), &device)?;
let c = a.matmul(&b)?;
println!("{c}");
Ok(())
}
```
`cargo run` should display a tensor of shape `Tensor[[2, 4], f32]`.
Having installed `candle` with Cuda support, simply define the `device` to be on GPU:
```diff
- let device = Device::Cpu;
+ let device = Device::new_cuda(0)?;
```
For more advanced examples, please have a look at the following section.
## Check out our examples
These online demos run entirely in your browser:
- [yolo](https://huggingface.co/spaces/lmz/candle-yolo): pose estimation and
object recognition.
- [whisper](https://huggingface.co/spaces/lmz/candle-whisper): speech recognition.
- [LLaMA2](https://huggingface.co/spaces/lmz/candle-llama2): text generation.
- [T5](https://huggingface.co/spaces/radames/Candle-T5-Generation-Wasm): text generation.
- [Phi-1.5, and Phi-2](https://huggingface.co/spaces/radames/Candle-Phi-1.5-Wasm): text generation.
- [Segment Anything Model](https://huggingface.co/spaces/radames/candle-segment-anything-wasm): Image segmentation.
- [BLIP](https://huggingface.co/spaces/radames/Candle-BLIP-Image-Captioning): image captioning.
We also provide a some command line based examples using state of the art models:
- [LLaMA and LLaMA-v2](./candle-examples/examples/llama/): general LLM, includes
the SOLAR-10.7B variant.
- [Falcon](./candle-examples/examples/falcon/): general LLM.
- [Phi-1, Phi-1.5, and Phi-2](./candle-examples/examples/phi/): 1.3b and 2.7b general LLMs with performance on par with LLaMA-v2 7b.
- [StableLM-3B-4E1T](./candle-examples/examples/stable-lm/): a 3b general LLM
pre-trained on 1T tokens of English and code datasets. Also supports
StableLM-2, a 1.6b LLM trained on 2T tokens, as well as the code variants.
- [Minimal Mamba](./candle-examples/examples/mamba-minimal/): a minimal
implementation of the Mamba state space model.
- [Mistral7b-v0.1](./candle-examples/examples/mistral/): a 7b general LLM with
better performance than all publicly available 13b models as of 2023-09-28.
- [Mixtral8x7b-v0.1](./candle-examples/examples/mixtral/): a sparse mixture of
experts 8x7b general LLM with better performance than a Llama 2 70B model with
much faster inference.
- [StarCoder](./candle-examples/examples/bigcode/): LLM specialized to code generation.
- [Replit-code-v1.5](./candle-examples/examples/replit-code/): a 3.3b LLM specialized for code completion.
- [Yi-6B / Yi-34B](./candle-examples/examples/yi/): two bilingual
(English/Chinese) general LLMs with 6b and 34b parameters.
- [Quantized LLaMA](./candle-examples/examples/quantized/): quantized version of
the LLaMA model using the same quantization techniques as
[llama.cpp](https://github.com/ggerganov/llama.cpp).
<img src="https://github.com/huggingface/candle/raw/main/candle-examples/examples/quantized/assets/aoc.gif" width="600">
- [Stable Diffusion](./candle-examples/examples/stable-diffusion/): text to
image generative model, support for the 1.5, 2.1, SDXL 1.0 and Turbo versions.
<img src="https://github.com/huggingface/candle/raw/main/candle-examples/examples/stable-diffusion/assets/stable-diffusion-xl.jpg" width="200">
- [Wuerstchen](./candle-examples/examples/wuerstchen/): another text to
image generative model.
<img src="https://github.com/huggingface/candle/raw/main/candle-examples/examples/wuerstchen/assets/cat.jpg" width="200">
- [yolo-v3](./candle-examples/examples/yolo-v3/) and
[yolo-v8](./candle-examples/examples/yolo-v8/): object detection and pose
estimation models.
<img src="https://github.com/huggingface/candle/raw/main/candle-examples/examples/yolo-v8/assets/bike.od.jpg" width="200"><img src="https://github.com/huggingface/candle/raw/main/candle-examples/examples/yolo-v8/assets/bike.pose.jpg" width="200">
- [segment-anything](./candle-examples/examples/segment-anything/): image
segmentation model with prompt.
<img src="https://github.com/huggingface/candle/raw/main/candle-examples/examples/segment-anything/assets/sam_merged.jpg" width="200">
- [Whisper](./candle-examples/examples/whisper/): speech recognition model.
- [T5](./candle-examples/examples/t5), [Bert](./candle-examples/examples/bert/),
[JinaBert](./candle-examples/examples/jina-bert/) : useful for sentence embeddings.
- [DINOv2](./candle-examples/examples/dinov2/): computer vision model trained
using self-supervision (can be used for imagenet classification, depth
evaluation, segmentation).
- [VGG](./candle-examples/examples/vgg/),
[RepVGG](./candle-examples/examples/repvgg): computer vision models.
- [BLIP](./candle-examples/examples/blip/): image to text model, can be used to
- [BLIP](./candle-examples/examples/blip/): image to text model, can be used to
generate captions for an image.
- [Marian-MT](./candle-examples/examples/marian-mt/): neural machine translation
model, generates the translated text from the input text.
Run them using commands like:
```
cargo run --example quantized --release
```
In order to use **CUDA** add `--features cuda` to the example command line. If
you have cuDNN installed, use `--features cudnn` for even more speedups.
There are also some wasm examples for whisper and
[llama2.c](https://github.com/karpathy/llama2.c). You can either build them with
`trunk` or try them online:
[whisper](https://huggingface.co/spaces/lmz/candle-whisper),
[llama2](https://huggingface.co/spaces/lmz/candle-llama2),
[T5](https://huggingface.co/spaces/radames/Candle-T5-Generation-Wasm),
[Phi-1.5, and Phi-2](https://huggingface.co/spaces/radames/Candle-Phi-1.5-Wasm),
[Segment Anything Model](https://huggingface.co/spaces/radames/candle-segment-anything-wasm).
For LLaMA2, run the following command to retrieve the weight files and start a
test server:
```bash
cd candle-wasm-examples/llama2-c
wget https://huggingface.co/spaces/lmz/candle-llama2/resolve/main/model.bin
wget https://huggingface.co/spaces/lmz/candle-llama2/resolve/main/tokenizer.json
trunk serve --release --port 8081
```
And then head over to
[http://localhost:8081/](http://localhost:8081/).
<!--- ANCHOR: useful_libraries --->
## Useful External Resources
- [`candle-tutorial`](https://github.com/ToluClassics/candle-tutorial): A
very detailed tutorial showing how to convert a PyTorch model to Candle.
- [`candle-lora`](https://github.com/EricLBuehler/candle-lora): Efficient and
ergonomic LoRA implementation for Candle. `candle-lora` has
out-of-the-box LoRA support for many models from Candle, which can be found
[here](https://github.com/EricLBuehler/candle-lora/tree/master/candle-lora-transformers/examples).
- [`optimisers`](https://github.com/KGrewal1/optimisers): A collection of optimisers
including SGD with momentum, AdaGrad, AdaDelta, AdaMax, NAdam, RAdam, and RMSprop.
- [`candle-vllm`](https://github.com/EricLBuehler/candle-vllm): Efficient platform for inference and
serving local LLMs including an OpenAI compatible API server.
- [`candle-ext`](https://github.com/mokeyish/candle-ext): An extension library to Candle that provides PyTorch functions not currently available in Candle.
- [`kalosm`](https://github.com/floneum/floneum/tree/master/interfaces/kalosm): A multi-modal meta-framework in Rust for interfacing with local pre-trained models with support for controlled generation, custom samplers, in-memory vector databases, audio transcription, and more.
- [`candle-sampling`](https://github.com/EricLBuehler/candle-sampling): Sampling techniques for Candle.
- [`gpt-from-scratch-rs`](https://github.com/jeroenvlek/gpt-from-scratch-rs): A port of Andrej Karpathy's _Let's build GPT_ tutorial on YouTube showcasing the Candle API on a toy problem.
If you have an addition to this list, please submit a pull request.
<!--- ANCHOR_END: useful_libraries --->
<!--- ANCHOR: features --->
## Features
- Simple syntax, looks and feels like PyTorch.
- Model training.
- Embed user-defined ops/kernels, such as [flash-attention v2](https://github.com/huggingface/candle/blob/89ba005962495f2bfbda286e185e9c3c7f5300a3/candle-flash-attn/src/lib.rs#L152).
- Backends.
- Optimized CPU backend with optional MKL support for x86 and Accelerate for macs.
- CUDA backend for efficiently running on GPUs, multiple GPU distribution via NCCL.
- WASM support, run your models in a browser.
- Included models.
- Language Models.
- LLaMA v1 and v2 with variants such as SOLAR-10.7B.
- Falcon.
- StarCoder.
- Phi 1, 1.5, and 2.
- Minimal Mamba
- Mistral 7b v0.1.
- Mixtral 8x7b v0.1.
- StableLM-3B-4E1T, StableLM-2-1.6B, Stable-Code-3B.
- Replit-code-v1.5-3B.
- Bert.
- Yi-6B and Yi-34B.
- Quantized LLMs.
- Llama 7b, 13b, 70b, as well as the chat and code variants.
- Mistral 7b, and 7b instruct.
- Mixtral 8x7b.
- Zephyr 7b a and b (Mistral-7b based).
- OpenChat 3.5 (Mistral-7b based).
- Text to text.
- T5 and its variants: FlanT5, UL2, MADLAD400 (translation), CoEdit (Grammar correction).
- Marian MT (Machine Translation).
- Whisper (multi-lingual support).
- Text to image.
- Stable Diffusion v1.5, v2.1, XL v1.0.
- Wurstchen v2.
- Image to text.
- BLIP.
- Computer Vision Models.
- DINOv2, ConvMixer, EfficientNet, ResNet, ViT, VGG, RepVGG, ConvNeXT.
- yolo-v3, yolo-v8.
- Segment-Anything Model (SAM).
- File formats: load models from safetensors, npz, ggml, or PyTorch files.
- Serverless (on CPU), small and fast deployments.
- Quantization support using the llama.cpp quantized types.
<!--- ANCHOR_END: features --->
## How to use
<!--- ANCHOR: cheatsheet --->
Cheatsheet:
| | Using PyTorch | Using Candle |
|------------|------------------------------------------|------------------------------------------------------------------|
| Creation | `torch.Tensor([[1, 2], [3, 4]])` | `Tensor::new(&[[1f32, 2.], [3., 4.]], &Device::Cpu)?` |
| Creation | `torch.zeros((2, 2))` | `Tensor::zeros((2, 2), DType::F32, &Device::Cpu)?` |
| Indexing | `tensor[:, :4]` | `tensor.i((.., ..4))?` |
| Operations | `tensor.view((2, 2))` | `tensor.reshape((2, 2))?` |
| Operations | `a.matmul(b)` | `a.matmul(&b)?` |
| Arithmetic | `a + b` | `&a + &b` |
| Device | `tensor.to(device="cuda")` | `tensor.to_device(&Device::new_cuda(0)?)?` |
| Dtype | `tensor.to(dtype=torch.float16)` | `tensor.to_dtype(&DType::F16)?` |
| Saving | `torch.save({"A": A}, "model.bin")` | `candle::safetensors::save(&HashMap::from([("A", A)]), "model.safetensors")?` |
| Loading | `weights = torch.load("model.bin")` | `candle::safetensors::load("model.safetensors", &device)` |
<!--- ANCHOR_END: cheatsheet --->
## Structure
- [candle-core](./candle-core): Core ops, devices, and `Tensor` struct definition
- [candle-nn](./candle-nn/): Tools to build real models
- [candle-examples](./candle-examples/): Examples of using the library in realistic settings
- [candle-kernels](./candle-kernels/): CUDA custom kernels
- [candle-datasets](./candle-datasets/): Datasets and data loaders.
- [candle-transformers](./candle-transformers): transformers-related utilities.
- [candle-flash-attn](./candle-flash-attn): Flash attention v2 layer.
- [candle-onnx](./candle-onnx/): ONNX model evaluation.
## FAQ
### Why should I use Candle?
Candle's core goal is to *make serverless inference possible*. Full machine learning frameworks like PyTorch
are very large, which makes creating instances on a cluster slow. Candle allows deployment of lightweight
binaries.
Secondly, Candle lets you *remove Python* from production workloads. Python overhead can seriously hurt performance,
and the [GIL](https://www.backblaze.com/blog/the-python-gil-past-present-and-future/) is a notorious source of headaches.
Finally, Rust is cool! A lot of the HF ecosystem already has Rust crates, like [safetensors](https://github.com/huggingface/safetensors) and [tokenizers](https://github.com/huggingface/tokenizers).
### Other ML frameworks
- [dfdx](https://github.com/coreylowman/dfdx) is a formidable crate, with shapes being included
in types. This prevents a lot of headaches by getting the compiler to complain about shape mismatches right off the bat.
However, we found that some features still require nightly, and writing code can be a bit daunting for non rust experts.
We're leveraging and contributing to other core crates for the runtime so hopefully both crates can benefit from each
other.
- [burn](https://github.com/burn-rs/burn) is a general crate that can leverage multiple backends so you can choose the best
engine for your workload.
- [tch-rs](https://github.com/LaurentMazare/tch-rs.git) Bindings to the torch library in Rust. Extremely versatile, but they
bring in the entire torch library into the runtime. The main contributor of `tch-rs` is also involved in the development
of `candle`.
### Common Errors
#### Missing symbols when compiling with the mkl feature.
If you get some missing symbols when compiling binaries/tests using the mkl
or accelerate features, e.g. for mkl you get:
```
= note: /usr/bin/ld: (....o): in function `blas::sgemm':
.../blas-0.22.0/src/lib.rs:1944: undefined reference to `sgemm_' collect2: error: ld returned 1 exit status
= note: some `extern` functions couldn't be found; some native libraries may need to be installed or have their path specified
= note: use the `-l` flag to specify native libraries to link
= note: use the `cargo:rustc-link-lib` directive to specify the native libraries to link with Cargo
```
or for accelerate:
```
Undefined symbols for architecture arm64:
"_dgemm_", referenced from:
candle_core::accelerate::dgemm::h1b71a038552bcabe in libcandle_core...
"_sgemm_", referenced from:
candle_core::accelerate::sgemm::h2cf21c592cba3c47 in libcandle_core...
ld: symbol(s) not found for architecture arm64
```
This is likely due to a missing linker flag that was needed to enable the mkl library. You
can try adding the following for mkl at the top of your binary:
```rust
extern crate intel_mkl_src;
```
or for accelerate:
```rust
extern crate accelerate_src;
```
#### Cannot run the LLaMA examples: access to source requires login credentials
```
Error: request error: https://huggingface.co/meta-llama/Llama-2-7b-hf/resolve/main/tokenizer.json: status code 401
```
This is likely because you're not permissioned for the LLaMA-v2 model. To fix
this, you have to register on the huggingface-hub, accept the [LLaMA-v2 model
conditions](https://huggingface.co/meta-llama/Llama-2-7b-hf), and set up your
authentication token. See issue
[#350](https://github.com/huggingface/candle/issues/350) for more details.
#### Missing cute/cutlass headers when compiling flash-attn
```
In file included from kernels/flash_fwd_launch_template.h:11:0,
from kernels/flash_fwd_hdim224_fp16_sm80.cu:5:
kernels/flash_fwd_kernel.h:8:10: fatal error: cute/algorithm/copy.hpp: No such file or directory
#include <cute/algorithm/copy.hpp>
^~~~~~~~~~~~~~~~~~~~~~~~~
compilation terminated.
Error: nvcc error while compiling:
```
[cutlass](https://github.com/NVIDIA/cutlass) is provided as a git submodule so you may want to run the following command to check it in properly.
```bash
git submodule update --init
```
#### Compiling with flash-attention fails
```
/usr/include/c++/11/bits/std_function.h:530:146: error: parameter packs not expanded with ‘...’:
```
This is a bug in gcc-11 triggered by the Cuda compiler. To fix this, install a different, supported gcc version - for example gcc-10, and specify the path to the compiler in the CANDLE_NVCC_CCBIN environment variable.
```
env CANDLE_NVCC_CCBIN=/usr/lib/gcc/x86_64-linux-gnu/10 cargo ...
```
#### Linking error on windows when running rustdoc or mdbook tests
```
Couldn't compile the test.
---- .\candle-book\src\inference\hub.md - Using_the_hub::Using_in_a_real_model_ (line 50) stdout ----
error: linking with `link.exe` failed: exit code: 1181
//very long chain of linking
= note: LINK : fatal error LNK1181: cannot open input file 'windows.0.48.5.lib'
```
Make sure you link all native libraries that might be located outside a project target, e.g., to run mdbook tests, you should run:
```
mdbook test candle-book -L .\target\debug\deps\ `
-L native=$env:USERPROFILE\.cargo\registry\src\index.crates.io-6f17d22bba15001f\windows_x86_64_msvc-0.42.2\lib `
-L native=$env:USERPROFILE\.cargo\registry\src\index.crates.io-6f17d22bba15001f\windows_x86_64_msvc-0.48.5\lib
```
#### Extremely slow model load time with WSL
This may be caused by the models being loaded from `/mnt/c`, more details on
[stackoverflow](https://stackoverflow.com/questions/68972448/why-is-wsl-extremely-slow-when-compared-with-native-windows-npm-yarn-processing).
#### Tracking down errors
You can set `RUST_BACKTRACE=1` to be provided with backtraces when a candle
error is generated.