3 #===============================================================================================================================
4 # Name : Résolution EF de l'équation de Poisson 2D -\triangle T = f avec conditions aux limites de Neumann T=0
5 # Author : Michaël Ndjinga
6 # Copyright : CEA Saclay 2019
7 # Description : Utilisation de la méthode des éléménts finis P1 avec champs T et f discrétisés aux noeuds d'un maillage triangulaire
8 # Création et sauvegarde du champ résultant ainsi que du champ second membre en utilisant la librairie CDMATH
9 # Comparaison de la solution numérique avec la solution exacte T=-cos(pi*x)*cos(pi*y)
10 #================================================================================================================================
12 import CoreFlows as cf
14 from math import cos, pi
16 def StationaryDiffusionEquation_2DEF_StructuredTriangles_Neumann():
18 # Prepare for the mesh
19 print("Building mesh " );
26 M=cm.Mesh(xinf,xsup,nx,yinf,ysup,ny,0)#Regular triangular mesh
27 # set the limit field for each boundary
29 M.setGroupAtPlan(xsup,0,eps,"Bord1")
30 M.setGroupAtPlan(xinf,0,eps,"Bord2")
31 M.setGroupAtPlan(ysup,1,eps,"Bord3")
32 M.setGroupAtPlan(yinf,1,eps,"Bord4")
34 print "Built a regular triangular 2D mesh from a square mesh with ", nx,"x" ,ny, " cells"
37 myProblem = cf.StationaryDiffusionEquation(spaceDim,FEComputation);
40 # set the boundary condition for each boundary
41 myProblem.setNeumannBoundaryCondition("Bord1")
42 myProblem.setNeumannBoundaryCondition("Bord2")
43 myProblem.setNeumannBoundaryCondition("Bord3")
44 myProblem.setNeumannBoundaryCondition("Bord4")
46 #Set the right hand side function
47 my_RHSfield = cm.Field("RHS_field", cm.NODES, M, 1)
48 for i in range(M.getNumberOfNodes()):
53 my_RHSfield[i]=2*pi*pi*cos(pi*x)*cos(pi*y)#mettre la fonction definie au second membre de l'edp
55 myProblem.setHeatPowerField(my_RHSfield)
56 myProblem.setLinearSolver(cf.GMRES,cf.ILU);
59 fileName = "StationnaryDiffusion_2DEF_StructuredTriangles_Neumann";
61 # computation parameters
62 myProblem.setFileName(fileName);
65 myProblem.initialize();
66 print("Running python "+ fileName );
68 ok = myProblem.solveStationaryProblem();
70 print( "Python simulation of " + fileName + " failed ! " );
73 ####################### Postprocessing #########################
74 my_ResultField = myProblem.getOutputTemperatureField()
75 #The following formulas use the fact that the exact solution is equal the right hand side divided by 2*pi*pi
76 max_abs_sol_exacte=max(my_RHSfield.max(),-my_RHSfield.min())/(2*pi*pi)
77 max_sol_num=my_ResultField.max()
78 min_sol_num=my_ResultField.min()
80 for i in range(M.getNumberOfNodes()) :
81 if erreur_abs < abs(my_RHSfield[i]/(2*pi*pi) - my_ResultField[i]) :
82 erreur_abs = abs(my_RHSfield[i]/(2*pi*pi) - my_ResultField[i])
84 print("Absolute error = max(| exact solution - numerical solution |) = ",erreur_abs )
85 print("Relative error = max(| exact solution - numerical solution |)/max(| exact solution |) = ",erreur_abs/max_abs_sol_exacte)
86 print ("Maximum numerical solution = ", max_sol_num, " Minimum numerical solution = ", min_sol_num)
88 assert erreur_abs/max_abs_sol_exacte <1.
91 print( "------------ !!! End of calculation !!! -----------" );
93 myProblem.terminate();
96 if __name__ == """__main__""":
97 StationaryDiffusionEquation_2DEF_StructuredTriangles_Neumann()