This project explains how to use the Fortran client (client.f90) with the C wrapper (api_wrapper.c) to interact with the Python Flask API (server.py) in the High-Performance Computing (HPC) Cluster.

# Matrix Inversion API Client-Server Example

This repository demonstrates how to use a Fortran client to send a matrix to a Python Flask API for inversion. Since Fortran does not have native support for HTTP requests, a C wrapper is used to handle the HTTP communication.

## Prerequisites

- **Fortran Compiler**: `gfortran` (GNU Fortran)
- **C Compiler**: `gcc` (GNU C Compiler)
- **cURL Library**: Required for HTTP requests in the C wrapper.
- **Python 3**: Required to run the Flask server.
- **Flask**: Python web framework.
- **NumPy**: Python library for numerical computations.

## Setup

### 1. Clone the Repository

```bash
git clone https://github.com/yourusername/matrix-api-client-server.git
cd matrix-api-client-server

2. Set Up the Python Environment

1. Create a virtual environment and activate it:

   $ python3 -m venv venv
   $ source venv/bin/activate

2. Install the required Python packages:

   $ pip install flask numpy

3. Compile the C Wrapper

The C wrapper (api_wrapper.c) uses the libcurl library to handle HTTP requests. Compile it as follows:

$ module load curl
$ gcc -c api_wrapper.c -o api_wrapper.o -lcurl

4. Compile the Fortran Client

The Fortran client (client.f90) calls the C wrapper to send the matrix to the server. Compile it as follows:

$ module load curl
$ gfortran -g client.f90 api_wrapper.o -o client -lcurl

5. Start the Flask Server

Run the Flask server (server.py) to handle incoming requests:

$ python server.py

The server will start on http://0.0.0.0:5000.

Usage

Running the Fortran Client

Once the server is running, execute the Fortran client:

$ ./client

The client will send a matrix to the server, receive the inverted matrix, and print both the original and inverted matrices.

Example Output

 Original matrix: 
 [[4.0, 7.0], [2.0, 6.0]]
 Server response: {"inverted_matrix": [[0.6, -0.7], [-0.2, 0.4]]}

Testing with cURL

You can also test the API directly using cURL:

curl -v -X POST http://172.20.11.21:5000/invert-matrix -H "Content-Type: application/json" -d '{"matrix": [[4.0, 7.0], [2.0, 6.0]]}'

Service Setup (Optional)

To run the Flask server as a service, you can use the provided server.service file. Follow these steps:

1. Copy the service file to the systemd directory:

   $ sudo cp server.service /etc/systemd/server.service

2. Reload the systemd daemon:

   $ sudo systemctl daemon-reload

3. Start and enable the service:

   $ sudo systemctl start server.service
   $ sudo systemctl enable server.service

License

This project is licensed under the MIT License. See the LICENSE file for details.

Contributing

Contributions are welcome! Please open an issue or submit a pull request for any improvements or bug fixes.

Acknowledgments

• Flask for the web framework.
• NumPy for matrix operations.
• libcurl for HTTP requests in C.