First commit of branch performance:

Bugs fixed:
- Solved an issue with particles being injected with infinite velocity
  resulting in Inf velocity in some cells of the output files.
- Particles are now equally distributed in cylindrical geometry along
  the radial direction.

New features:
- Particles now have their own weight that is recalculated when the
  particle moves to a new cell. This avoid the reduction of density at
  r = 0.

Cases:
- Added a case of Argon flow around a cylinder to measure performance
  and future improvements.

src/modules/moduleInject.f95

@@ -9,7 +9,10 @@ MODULE moduleInject
     REAL(8):: n(1:3) !Direction of injection
     INTEGER:: nParticles !Number of particles to introduce each time step
     INTEGER:: pt !Species of injection
+    INTEGER:: nEdges
     INTEGER, ALLOCATABLE:: edges(:) !Array with edges
+    REAL(8), ALLOCATABLE:: weight(:) !weight of cells for injection
+    REAL(8):: sumWeight
     CONTAINS
       PROCEDURE, PASS:: init         => initInject
       PROCEDURE, PASS:: addParticles => addParticlesMaxwellian
@@ -22,6 +25,7 @@ MODULE moduleInject
   CONTAINS
     SUBROUTINE initInject(self, i, v, n, T, flow, pt, physicalSurface)
       USE moduleMesh
+      USE moduleMeshCyl
       USE moduleRefParam
       USE moduleConstParam
       USE moduleSpecies
@@ -32,7 +36,7 @@ MODULE moduleInject
       REAL(8), INTENT(in):: v, n(1:3), T(1:3)
       INTEGER, INTENT(in):: pt, physicalSurface
       REAL(8), INTENT(in):: flow
-      INTEGER:: nEdges, e, et
+      INTEGER:: e, et
       INTEGER:: phSurface(1:mesh%numEdges)
 
       self%id         = i
@@ -49,17 +53,24 @@ MODULE moduleInject
 
       END DO
 
-      nEdges = COUNT(phSurface == physicalSurface)
-      ALLOCATE(inject(i)%edges(1:nEdges))
+      self%nEdges = COUNT(phSurface == physicalSurface)
+      ALLOCATE(inject(i)%edges(1:self%nEdges))
+      ALLOCATE(inject(i)%weight(1:self%nEdges))
       et = 0
       DO e=1, mesh%numEdges
         IF (mesh%edges(e)%obj%physicalSurface == physicalSurface) THEN
           et = et + 1
-          self%edges(et) = mesh%edges(e)%obj%n
+          self%edges(et)  = mesh%edges(e)%obj%n
+          SELECT TYPE(edge => mesh%edges(e)%obj)
+          CLASS IS (meshEdgeCyl)
+            self%weight(et) = (edge%r(1)+edge%r(2))/2.D0
+
+          END SELECT
 
         END IF
 
       END DO
+      self%sumWeight = SUM(self%weight)
       nPartInj = nPartInj + self%nParticles
 
     END SUBROUTINE
@@ -70,8 +81,11 @@ MODULE moduleInject
       REAL(8), INTENT (in):: u, vth
       REAL(8):: x, y
       vBC=0.D0
+      x = 0.D0
 
-      x=RAND()
+      DO WHILE (x == 0.D0)
+        x=RAND()
+      END DO
       y=RAND()
 
       vBC = u + vth*DSQRT(-2.D0*DLOG(x))*DCOS(2.D0*PI*y)
@@ -86,6 +100,8 @@ MODULE moduleInject
       IMPLICIT NONE
 
       CLASS(injectGeneric), INTENT(in):: self
+      REAL(8):: randomX
+      INTEGER:: j
       INTEGER:: randomEdge
       REAL(8):: randomPos
       REAL(8):: vVec(1:3), vTh(1:3)
@@ -93,15 +109,31 @@ MODULE moduleInject
       INTEGER:: n1 = 0, n2 = 0
       !Edge nodes coordinates
       REAL(8):: p1(1:3) = 0.D0, p2(1:3) = 0.D0
+      INTEGER:: nMin, nMax !Min and Max index in part_inj array
       INTEGER:: n
 
       vVec = self%v * self%n
       vTh  = DSQRT(self%T/species(self%pt)%obj%m)
 
       !Insert particles
-      DO n = 1, self%nParticles
+      !TODO: Adjust for multiple injections
+      nMin = 1
+      nMax = self%nParticles
+      !Assign particle type
+      part_inj(nMin:nMax)%pt = self%pt
+      !Assign weight to particle.
+      part_inj(nMin:nMax)%weight = species(self%pt)%obj%weight
+      part_inj(nMin:nMax)%n_in = .TRUE.
+      DO n = nMin, nMax
         !Select edge randomly from which inject particle
-        randomEdge = self%edges(INT(RAND()*(SIZE(self%edges)-1)+1))
+        randomX = RAND()*self%sumWeight
+        DO j = 1, self%nEdges
+          IF (randomX < self%weight(j)) EXIT
+          randomX = randomX - self%weight(j)
+
+        END DO
+
+        randomEdge = self%edges(j)
 
         !Get coordinates of edge nodes
         SELECT TYPE(edge => mesh%edges(randomEdge)%obj)
@@ -132,8 +164,6 @@ MODULE moduleInject
 
         END IF
 
-        part_inj(n)%pt = self%pt
-        part_inj(n)%n_in = .TRUE.
         part_inj(n)%v = (/ vBC(vVec(1), vTh(1)), &
                            vBC(vVec(2), vTh(2)), &
                            vBC(vVec(3), vTh(3)) /)
@@ -145,6 +175,7 @@ MODULE moduleInject
         part_inj(n)%r(2) = p1(2) + randomPos*(p2(2) - p1(2))
         part_inj(n)%r(3) = p1(3) + randomPos*(p2(3) - p1(3))
 
+
         !Push new particle
         CALL push(part_inj(n))