Document MPI smoke-test CI

Author: Kandil2001

README.md

@@ -4,9 +4,12 @@
   <img src="https://img.shields.io/badge/Status-Completed-brightgreen.svg" alt="Completed">
   <img src="https://img.shields.io/badge/Language-C99-blue.svg" alt="C99">
   <img src="https://img.shields.io/badge/Parallelism-MPI-green.svg" alt="MPI">
+  <a href="https://github.com/Kandil2001/Distributed-TSP-Solver/actions/workflows/ci.yml">
+    <img src="https://github.com/Kandil2001/Distributed-TSP-Solver/actions/workflows/ci.yml/badge.svg" alt="MPI build and smoke test">
+  </a>
   <img src="https://img.shields.io/badge/License-MIT-lightgrey.svg" alt="MIT License">
-  <a href="https://kandil2001.github.io/">
-    <img src="https://img.shields.io/badge/Portfolio-kandil2001.github.io-2ea44f.svg" alt="Portfolio">
+  <a href="https://kandil2001.github.io/projects/distributed-tsp.html">
+    <img src="https://img.shields.io/badge/Portfolio-Case%20Study-2ea44f.svg" alt="Portfolio case study">
   </a>
 </p>
 
@@ -28,6 +31,7 @@ The project was developed for a High Performance Computing course at Bergische U
 - deadlock-free communication between neighboring MPI ranks
 - strong-scaling measurements across several process counts
 - Octave scripts for runtime, efficiency, and route-quality plots
+- GitHub Actions production build and two-rank smoke execution
 
 ## How the solver works
 
@@ -102,6 +106,21 @@ Submit the cluster scaling study with:
 sbatch script/scaling_test.sh
 ```
 
+## Continuous integration
+
+The GitHub Actions workflow performs two separate checks:
+
+1. it builds the production solver with the unchanged scientific defaults
+2. it builds a temporary reduced-iteration binary in the CI runner and executes it with two MPI ranks
+
+The smoke run verifies that:
+
+- MPI communication completes without hanging
+- the global reduction returns a finite positive route length
+- the saved route is a valid permutation of all 52 Berlin52 cities
+
+The temporary iteration reduction is used only to keep CI fast. It does not change the repository’s production solver or the published scaling results.
+
 ## Repository structure
 
 ```text
@@ -110,6 +129,7 @@ script/scaling_test.sh      cluster scaling study
 script/plot_*.m             Octave plotting scripts
 data/berlin52.tsp           included benchmark case
 figures/                    selected published plots
+.github/workflows/ci.yml    production build and MPI smoke test
 Makefile                    local build configuration
 ```