0D Grid geometry

Implementation of the 0D grid to test collisional processes.

An OMP_LOCK was added to the nodes to properly write perform the
scattering (it is weird that multiple threads work in the same node at
the same time, but in 0D happens everytime).

Added a new case to test the 0D geometry.

User Manual updated with the new options.

src/modules/moduleInput.f90

@@ -348,7 +348,6 @@ MODULE moduleInput
               !Assign particle to temporal list of particles
               CALL partInitial%add(partNew)
 
-
             END DO
 
             DEALLOCATE(source)
@@ -768,6 +767,7 @@ MODULE moduleInput
       USE moduleMesh1DCart, ONLY: connectMesh1DCart
       USE moduleErrors
       USE moduleOutput
+      USE moduleRefParam
       USE json_module
       IMPLICIT NONE
 
@@ -776,6 +776,7 @@ MODULE moduleInput
       LOGICAL:: doubleMesh
       CHARACTER(:), ALLOCATABLE:: meshFormat, meshFile
       CHARACTER(:), ALLOCATABLE:: fullPath
+      REAL(8):: volume
 
       !Firstly, indicates if a specific mesh for MC collisions is being use
       doubleMesh = ASSOCIATED(meshForMCC, meshColl)
@@ -792,6 +793,7 @@ MODULE moduleInput
         IF (doubleMesh) CALL initGmsh2(meshColl)
 
       CASE ("0D")
+        CALL config%get('geometry.meshType', meshFormat, found)
         CALL init0D(mesh)
 
       CASE DEFAULT
@@ -812,6 +814,18 @@ MODULE moduleInput
 
       END IF
 
+      !Gets the volume for a 0D mesh
+      !TODO: Try to constrain this to the inout for 0D
+      IF (meshFormat == "0D") THEN
+        CALL config%get('geometry.volume', volume, found)
+        IF (found) THEN
+          mesh%vols(1)%obj%volume = mesh%vols(1)%obj%volume*volume / Vol_ref
+          mesh%nodes(1)%obj%v     = mesh%vols(1)%obj%volume
+
+        END IF
+
+      END IF
+
       !Creates the connectivity between elements
       SELECT CASE(mesh%geometry)
       CASE("3DCart")