Julia_to_AzureFunc_solver_v1

Step 1: Set Up the Azure Function Project

• Install the Azure Functions Core Tools

• If you haven't already, install the Azure Functions Core Tools. You can find installation instructions here.

Step 1.2: Create a New Azure Functions Project

• Open a terminal or command prompt and create a new Azure Functions project:

func init LinearOptimizerFunction --dotnet  
cd LinearOptimizerFunction  
func new --name LinearOptimizer --template "HTTP trigger" --authlevel "anonymous"  

• This will create a new Azure Functions project with a function named LinearOptimizer.

Step 1.3: Copy the Shared Library

• Place your linear_optimizer.dll (or the appropriate shared library for your OS) into the project directory. Optionally, create a lib directory to keep things organized:

mkdir lib  
cp /path/to/linear_optimizer.dll lib/  

Step 2: Implement the Azure Function

1. Modify the Function Code

2. Open the LinearOptimizer.cs file in your favorite text editor and replace its contents with the following code:

using System;  
using System.IO;  
using System.Runtime.InteropServices;  
using System.Threading.Tasks;  
using Microsoft.AspNetCore.Mvc;  
using Microsoft.Azure.WebJobs;  
using Microsoft.Azure.WebJobs.Extensions.Http;  
using Microsoft.AspNetCore.Http;  
using Microsoft.Extensions.Logging;  
using Newtonsoft.Json;  
  
public static class LinearOptimizer  
{  
    // Import the solve_linear_problem function from the DLL  
    [DllImport("lib/linear_optimizer.dll", CallingConvention = CallingConvention.Cdecl)]  
    public static extern IntPtr solve_linear_problem(double[] c, int c_len, double[,] A, int A_rows, int A_cols, double[] b, int b_len);  
  
    // Import a function to free the memory allocated in Julia (if you have implemented one)  
    [DllImport("lib/linear_optimizer.dll", CallingConvention = CallingConvention.Cdecl)]  
    public static extern void free_result(IntPtr ptr);  
  
    [FunctionName("LinearOptimizer")]  
    public static async Task<IActionResult> Run(  
        [HttpTrigger(AuthorizationLevel.Function, "post", Route = "glopar/v3")] HttpRequest req,  
        ILogger log)  
    {  
        log.LogInformation("C# HTTP trigger function processed a request.");  
  
        string requestBody = await new StreamReader(req.Body).ReadToEndAsync();  
        dynamic data = JsonConvert.DeserializeObject(requestBody);  
  
        double[] c = data.c.ToObject<double[]>();  
        double[,] A = data.A.ToObject<double[,]>();  
        double[] b = data.b.ToObject<double[]>();  
  
        // Call the Julia function  
        IntPtr resultPtr = solve_linear_problem(c, c.Length, A, A.GetLength(0), A.GetLength(1), b, b.Length);  
  
        // Check if the resultPtr is not null  
        if (resultPtr == IntPtr.Zero)  
        {  
            return new BadRequestObjectResult("Optimization failed.");  
        }  
  
        // Allocate memory for the result  
        double[] result = new double[c.Length];  
        Marshal.Copy(resultPtr, result, 0, c.Length);  
  
        // Free the allocated memory  
        free_result(resultPtr);  
  
        return new OkObjectResult(result);  
    }  
}  

Step 3: Build and Test the Azure Function Locally

• In the terminal or command prompt, build the project:

dotnet build

Step 3.2: Run the Project Locally

• Run the Azure Function locally to test it:

func start Type user query here. (Shift + Enter for new line)