diff --git a/README.md b/README.md
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--- a/README.md
+++ b/README.md
@@ -84,4 +84,12 @@ prakhars962/deepinn   <none>        fe16ca34f9d9   About an hour ago   6.8GB
 The only solution is to delete them one by one using the IMAGE_ID.
 ```sh
 docker image rm -f IMAGE_ID
+```
+
+### UML diagram
+The UML diagram is generated using `pyreverse`. This provides an overview of the codebase.
+
+```sh
+cd UML\ diagrams
+pyreverse -o pdf ../DeepINN/
 ```
\ No newline at end of file
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diff --git a/todo.md b/todo.md
index 9f14fe2..1cf9d25 100644
--- a/todo.md
+++ b/todo.md
@@ -15,9 +15,9 @@ Last work : `DeepINN/constraint/gradients.py`
 ## Constraints
 - [X] Implement the prescribed BC part in constraint/ boundary_loss dirichletBC.
 - [X] Implement PDE loss constraint.
-- [ ] Implement gradients.
+- [x] Implement gradients.
 - [ ] Implement lazy evaluation of gradients.
-- [ ] Implement more constrainst.
+- [ ] Implement more constraint.
 
 ## Architectures
 - [x] Implement fully connected NN.
@@ -27,7 +27,7 @@ Last work : `DeepINN/constraint/gradients.py`
 - [x] Basic geometry tutorials.
 - [x] Constraints tutorials.
 - [ ] Add template PDE in constraint directory.
-- [ ] There is some problem with FCNN tutorial. probably the feature scaling isn't working.
+- [x] There was some problem with FCNN tutorial. It was incorrect PDE.
 
 ## Misc
 - [x] Migrate to JupyterBooks.