mv solution of matrix in dive into function as in course

source/Dive_into_Functions.rst

@@ -492,4 +492,36 @@ This function have to take the phase as parameter
 
 :download:`translate.py <_static/code/translate.py>` .  
 
-    
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+
+.. _matrix_exercise:
+
+Exercise
+--------
+
+Write a program that calculates the similarity of 2 RNA sequences.
+
+* To compute the similarity you need to parse a file containing the :download:`similarity matrix <_static/data/similarity_matrix>`.
+
+  **Hint**: use the module containing the functions that handle a matrix from previous chapter.
+  put this matrix.py file in a directory named "my_python_lib" in your home or Desktop
+  and import it in your current program (the similarity script must be placed elsewhere).
+* The similarity of the 2 sequences is the sum of base similarities.
+  so you have to compare the first base of two sequences and use the matrix to get the similarity
+  from the similarity table, on so on for all bases then sum these similarities.
+
+First implementation
+
+.. literalinclude:: _static/code/matrix.py
+   :linenos:
+   :language: python
+
+:download:`matrix.py <_static/code/matrix.py>` .
+
+
+Second implementation
+
+.. literalinclude:: _static/code/matrix2.py
+   :linenos:
+   :language: python
+
+:download:`matrix2.py <_static/code/matrix2.py>` .