diff --git a/README.md b/README.md
index 83aaa8c..0c2c85e 100644
--- a/README.md
+++ b/README.md
@@ -53,6 +53,13 @@ Adding support for non vectorized solvers ('fmincon', 'fminbnd', or 'fminsearch'
 
 * **Thomas Guillod, ETH Zurich, Power Electronic Systems Laboratory** - [GitHub Profile](https://github.com/otvam)
 
+## Function calling structure
+
+<p float="middle">
+    <img src="readme_img/CallerStructure.png" width="800">
+</p>
+
+
 ## License
 
 * This project is licensed under the **BSD License**, see [LICENSE.md](LICENSE.md).
diff --git a/readme_img/CallerStructure.png b/readme_img/CallerStructure.png
new file mode 100644
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