add readme

Author: js1010

README.md

@@ -1,5 +1,10 @@
+### Introduction
+
+This project is to speed up various ML models (e.g. topic modeling, word embedding, etc) by CUDA. It would be nice to think of it as [gensim](https://github.com/RaRe-Technologies/gensim)'s GPU version project. As a starting step, I implemented the most widely used word embedding model, the [word2vec](https://arxiv.org/pdf/1301.3781.pdf) model, and the most representative topic model, the [LDA (Latent Dirichlet Allocation)](https://www.jmlr.org/papers/volume3/blei03a/blei03a.pdf) model.
+
 ### How to install
 
+- install from source
 
 ```shell
 # clone repo and submodules
@@ -14,3 +19,12 @@ python -m grpc_tools.protoc --python_out cusim/ --proto_path cusim/proto/ config
 # install
 python setup.py install
 ```
+
+- pip installation will be available soon
+
+### How to use
+
+- `examples/example1.py` and `examples/README.md` will be very helpful to understand the usage.
+- paremeter description can be seen in `cusim/proto/config.proto`
+
+### Performance