Exemple n°5

In this example, we will show an example of using table reading/filling via the position of a pointer.

Indeed, until now, we have filled our tables of values with line/column names, placing the values next to each other. It turns out that internally, when an element is added or modified, there is a pointer that updates and points to the last manipulated element.

Remarks

Pointer in the sense of "pointer to a position in the 2D array," not in the sense of "C pointer to a memory area."

We can therefore use this pointer to modify values around the last manipulated value.

Results_Example5	Iteration 1	Iteration 2	Iteration 3	Somme
Nb de Fissions	36	0	85	121
Nb de Fissions (div par 2)	18	0	42.5	60.5
Nb de Collisions	29	84	21	134
Nb de Collisions (div par 2)	14.5	42	10.5	67

Initial entry point

Let's look at the start-init entry point:

SimpleTableOutputExample5Module.cc

void SimpleTableOutputExample5Module::
initModule()
{
  srand(1234);
  options()->stOutput()->init();
 
  StringUniqueArray columns_name(NB_ITER);
  for(Integer i = 0; i < NB_ITER; i++){
    columns_name[i] = "Iteration " + String::fromNumber(i+1);
  }
  options()->stOutput()->addColumns(columns_name);
 
  // On ajoute aussi quatre lignes.
  // Toujours dans un soucis d'optimisation, on peut créer les lignes et récupérer
  // leur position pour la suite, ainsi, on évite deux recherches de String dans un
  // tableau de String à chaque itération.
  options()->stOutput()->addRows(StringUniqueArray{
    "Nb de Fissions", 
    "Nb de Fissions (div par 2)", 
    "Nb de Collisions", 
    "Nb de Collisions (div par 2)"});
 
  pos_fis = options()->stOutput()->rowPosition("Nb de Fissions");
  pos_col = options()->stOutput()->rowPosition("Nb de Collisions");
 
  options()->stOutput()->print();
}

Here, nothing particularly original, apart from the two extra lines: (div by 2). These two lines will contain the number of fissions/collisions in an iteration divided by 2.

Loop entry point

Let's look at the compute-loop entry point:

SimpleTableOutputExample5Module.cc

void SimpleTableOutputExample5Module::
loopModule()
{
  Integer nb_fissions = rand()%99;
  Integer nb_collisions = rand()%99;
 
  // Ici, on utilise editElementDown() pour ajouter un élement sous l'élement dernièrement
  // modifié.
  options()->stOutput()->addElementInRow(pos_fis, nb_fissions);
  options()->stOutput()->editElementDown(nb_fissions/2.);
  options()->stOutput()->addElementInRow(pos_col, nb_collisions);
  options()->stOutput()->editElementDown(nb_collisions/2.);
 
  options()->stOutput()->print();
  if (m_global_iteration() == NB_ITER)
    subDomain()->timeLoopMng()->stopComputeLoop(true);
}

A new method appears: ISimpleTableOutput::editElementDown(). This method allows modifying the "cell" below the "cell" that was just modified. Let's take the two lines dedicated to fission. The first line adds a value to the Nb de Fissions line. Internally, a pointer is modified and now points to the value that was just added. The second line calls the new method. This method will take the pointer, search for the "cell" below, and replace its value with nb_fissions/2. By default, the pointer will then be updated and point to this manipulated "cell." So if we wanted to add, for example, nb_fissions*2 right below, we could make another call to the ISimpleTableOutput::editElementDown() method right after.

In the case where there is a modification of nb_fissions between the two lines (without touching the table):

options()->csvOutput()->addElementInRow(pos_fis, nb_fissions);
nb_fissions += 456;
options()->csvOutput()->editElementDown(nb_fissions/2.); // Pas la bonne valeur !!!

We could do this:

options()->csvOutput()->addElementInRow(pos_fis, nb_fissions);
nb_fissions += 456;
options()->csvOutput()->editElementDown(element()/2.); // C'est correct !!!

ISimpleTableOutput::element() is a method that allows retrieving the value of the "cell" pointed to by the pointer. This can be practical in this case, for example (we agree that if we don't use the pointer and the associated methods, it's a useless method).

Note

There is not only the ISimpleTableOutput::editElementDown() method; there are equivalent methods for the four directions: ISimpleTableOutput::editElementUp() ISimpleTableOutput::editElementLeft() ISimpleTableOutput::editElementRight() Same for ISimpleTableOutput::element().

Exit entry point

Finally, let's look at the exit entry point:

SimpleTableOutputExample5Module.cc

void SimpleTableOutputExample5Module::
endModule()
{
  for(Integer pos = 0; pos < options()->stOutput()->numberOfRows(); pos++) {
    RealUniqueArray row = options()->stOutput()->row(pos);
    Real sum = 0.;
    for(Real elem : row) {
      sum += elem;
    }
    options()->stOutput()->addElementInColumn("Somme", sum);
  }
 
  options()->stOutput()->print();
  options()->stOutput()->writeFile();
}

This entry point is identical to that of the previous example.

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Example n°4 Example No. 6