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/mesh/inout/0D/moduleMeshInput0D.f90

@@ -19,6 +19,7 @@ MODULE moduleMeshInput0D
         TYPE IS(meshParticles)
           self%printOutput => printOutput0D
           self%printEM     => printEM0D
+          self%readInitial => readInitial0D
 
         END SELECT
         self%readMesh => read0D
@@ -63,4 +64,37 @@ MODULE moduleMeshInput0D
 
     END SUBROUTINE read0D
 
+    SUBROUTINE readInitial0D(sp, filename, density, velocity, temperature)
+      IMPLICIT NONE
+
+      INTEGER, INTENT(in):: sp
+      CHARACTER(:), ALLOCATABLE, INTENT(in):: filename
+      REAL(8), ALLOCATABLE, INTENT(out), DIMENSION(:):: density
+      REAL(8), ALLOCATABLE, INTENT(out), DIMENSION(:,:):: velocity
+      REAL(8), ALLOCATABLE, INTENT(out), DIMENSION(:):: temperature
+      REAL(8):: dummy
+      INTEGER:: stat
+
+      ALLOCATE(density(1:1))
+      ALLOCATE(velocity(1:1, 1:3))
+      ALLOCATE(temperature(1:1))
+
+      OPEN(10, file = TRIM(filename))
+      
+      !Finds the last line of data
+      stat = 0
+      DO WHILE (stat==0)
+        READ(10, *, iostat = stat)
+
+      END DO
+
+      !Go back two line
+      BACKSPACE(10)
+      BACKSPACE(10)
+
+      !Reads data
+      READ(10, *) dummy, density(1), velocity(1, 1:3), dummy, temperature(1)
+
+    END SUBROUTINE readInitial0D
+
 END MODULE moduleMeshInput0D