# Quick Demo

Colossal-AI is an integrated large-scale deep learning system with efficient parallelization techniques. The system can accelerate model training on distributed systems with multiple GPUs by applying parallelization techniques. The system can also run on systems with only one GPU. Quick demos showing how to use Colossal-AI are given below.

## Single GPU​

Colossal-AI can be used to train deep learning models on systems with only one GPU and achieve baseline performances. We provided an example to train ResNet on CIFAR10 dataset with only one GPU. You can find the example in ColossalAI-Examples. Detailed instructions can be found in its README.md.

## Multiple GPUs​

Colossal-AI can be used to train deep learning models on distributed systems with multiple GPUs and accelerate the training process drastically by applying efficient parallelization techniques. When we have several parallelism for you to try out.

#### 1. data parallel​

You can use the same ResNet example as the single-GPU demo above. By setting --nproc_per_node to be the number of GPUs you have on your machine, the example is turned into a data parallel example.

#### 2. hybrid parallel​

Hybrid parallel includes data, tensor, and pipeline parallelism. In Colossal-AI, we support different types of tensor parallelism (i.e. 1D, 2D, 2.5D and 3D). You can switch between different tensor parallelism by simply changing the configuration in the config.py. You can follow the GPT example. Detailed instructions can be found in its README.md.

#### 3. MoE parallel​

We provided an example of WideNet to demonstrate MoE parallelism. WideNet uses mixture of experts (MoE) to achieve better performance. More details can be found in Tutorial: Integrate Mixture-of-Experts Into Your Model

#### 4. sequence parallel​

Sequence parallel is designed to tackle memory efficiency and sequence length limit problems in NLP tasks. We provided an example of BERT in ColossalAI-Examples. You can follow the README.md to execute the code.