WIP: Add Python code for couple your code section

Author: kss682

pages/docs/couple-your-code/couple-your-code-preparing-your-solver.md

@@ -7,6 +7,13 @@ summary: "If you want to couple your own code you need to properly understand it
 
 Let's say you want to prepare a fluid solver for fluid-structure interaction and that your code looks like this:
 
+<ul id="apiTabs" class="nav nav-tabs">
+    <li class="active"><a href="#cpp" data-toggle="tab">C++</a></li>
+    <li><a href="#python" data-toggle="tab">Python</a></li>
+</ul>
+<div class="tab-content">
+  <div role="tabpanel" class="tab-pane active" id="cpp" markdown="1">
+
 ```cpp
 turnOnSolver(); //e.g. setup and partition mesh
 
@@ -18,8 +25,25 @@ while (not simulationDone()){ // time loop
   endTimeStep(); // e.g. update variables, increment time
 }
 turnOffSolver();
+
+```
+
+</div>
+<div role="tabpanel" class="tab-pane" id="python" markdown="1">
+
+```python
+turn_on_solver() #e.g. setup and partition mesh
+
+while not simulation_done(): # time loop
+  dt = begin_time_step() #e.g compute adaptive dt
+  solve_time_step(dt)
+  end_time_step() #e.g. update variables, increment time
+
+turn_off_solver()
 ```
 
+</div>
+</div>
 Probably most solvers have such a structures: something in the beginning (reading input, domain decomposition), a big time loop, and something in the end. Each time step also falls into three parts: some pre-computations (e.g. computing an adaptive time step size), the actual computation (solving a linear or non-linear equation system), and something in the end (updating variables, incrementing time). Try to identify these parts in the code you want to couple.
 
 In the following steps, we will slowly add more and more calls to the preCICE API in this code snippet. Some part of the preCICE API is briefly described in each step. More precisely (no pun intended :grin:), we use the native `C++` API of preCICE. The API is, however, also available in other scientific programming languages: plain `C`, `Fortran`, `Python`, `Matlab`, `Julia`, and `Rust` (see [Application Programming Interface](couple-your-code-api)).

pages/docs/couple-your-code/couple-your-code-steering-methods.md

@@ -9,28 +9,65 @@ summary: "In this step, you get to know the most important API functions of preC
 As a first preparation step, you need to include the preCICE library headers. In C++, you need to include the file [precice.hpp](https://github.com/precice/precice/blob/develop/src/precice/precice.hpp).
 The handle to the preCICE API is the class `precice::Participant`. Its constructor requires the participant's name, the preCICE configuration file's name and the `rank` and `size` of the current thread. Once the basic preCICE interface is set up, we can _steer_ the behaviour of preCICE. For that we need the following functions:
 
+<ul id="apiTabs" class="nav nav-tabs">
+    <li class="active"><a href="#cpp-1" data-toggle="tab">C++</a></li>
+    <li><a href="#python-1" data-toggle="tab">Python</a></li>
+</ul>
+<div class="tab-content">
+  <div role="tabpanel" class="tab-pane active" id="cpp-1" markdown="1">
+
 ```cpp
 Participant( String participantName, String configurationFileName, int rank, int size );
 void initialize();
 void advance ( double computedTimeStepSize );
 void finalize();
 ```
 
+  </div>
+  <div role="tabpanel" class="tab-pane" id="python-1" markdown="1">
+
+```python
+"""
+  Parameters:
+  participant_name: string
+    Name of the solver
+  configuration_file_name: string
+    Name of preCICE config file
+  rank: int
+    Rank of the process
+  size: int
+    Size of the process
+"""
+participant = Participant(participant_name, configuration_file_name, rank, size)
+
+participant.initialize()
+
+"""
+  Parameters:
+  computed_timestep_size: double
+    Length of timestep used by solver
+"""
+participant.advance(computed_timestep_size)
+
+participant.finalize()
+
+```
+
+  </div>
+</div>
 What do they do?
 
 * `initialize` establishes communication channels and sets up data structures of preCICE.
 * `advance` needs to be called after the computation of every time step to _advance_ the coupling. As an argument, you have to pass the solver's last time step size (`dt`). Additionally, it maps coupling data between the coupling meshes, it communicates coupling data between the coupled participants, and it accelerates coupling data. One could say the complete coupling happens within this single function.
 * `finalize` frees the preCICE data structures and closes communication channels.
 
 The following function allows us to query the maximum allowed time step size from preCICE:
-
-
 <ul id="apiTabs" class="nav nav-tabs">
-    <li class="active"><a href="#cpp" data-toggle="tab">C++</a></li>
-    <li><a href="#python" data-toggle="tab">Python</a></li>
+    <li class="active"><a href="#cpp-2" data-toggle="tab">C++</a></li>
+    <li><a href="#python-2" data-toggle="tab">Python</a></li>
 </ul>
 <div class="tab-content">
-  <div role="tabpanel" class="tab-pane active" id="cpp" markdown="1">
+  <div role="tabpanel" class="tab-pane active" id="cpp-2" markdown="1">
 ```cpp
 double getMaxTimeStepSize();
 ```
@@ -60,8 +97,10 @@ while (not simulationDone()){ // time loop
 precice.finalize(); // frees data structures and closes communication channels
 turnOffSolver();
 ```
+
   </div>
-  <div role="tabpanel" class="tab-pane" id="python" markdown="1">
+  <div role="tabpanel" class="tab-pane" id="python-2" markdown="1">
+
 ```python
 import precice
 
@@ -82,7 +121,8 @@ while t < t_end:  # time loop
     t = t + dt
 
 precice.finalize()  # frees data structures and closes communication channels
+
 ```
+
   </div>
 </div>
-