Implementation of different distribution functions for velocities.

Maxwellian and Diract Delta distributions have been implemented.

The input for injection of particles should be rewritten to allow more
clear input file.

src/modules/moduleInject.f90

@@ -1,21 +1,63 @@
 !injection of particles
 MODULE moduleInject
 
+  !Generic type for velocity distribution function
+  TYPE, ABSTRACT:: velDistGeneric
+    CONTAINS
+      !Returns random velocity from distribution function
+      PROCEDURE(randomVel_interface), DEFERRED, PASS:: randomVel
+
+  END TYPE velDistGeneric
+
+  ABSTRACT INTERFACE
+    FUNCTION randomVel_interface(self) RESULT(v)
+      IMPORT velDistGeneric
+
+      CLASS(velDistGeneric), INTENT(in):: self
+      REAL(8):: v
+
+    END FUNCTION randomVel_interface
+
+  END INTERFACE
+
+  !Container for velocity distributions
+  TYPE:: velDistCont
+    CLASS(velDistGeneric), ALLOCATABLE:: obj
+
+  END TYPE velDistCont
+
+  !Maxwellian distribution function
+  TYPE, EXTENDS(velDistGeneric):: velDistMaxwellian
+    REAL(8):: v !Velocity
+    REAL(8):: vTh !Thermal Velocity
+    CONTAINS
+      PROCEDURE, PASS:: randomVel => randomVelMaxwellian
+  
+  END TYPE velDistMaxwellian
+
+  !Dirac's delta distribution function
+  TYPE, EXTENDS(velDistGeneric):: velDistDelta
+    REAL(8):: v !Velocity
+    CONTAINS
+      PROCEDURE, PASS:: randomVel => randomVelDelta
+
+  END TYPE velDistDelta
+
+  !Generic injection of particles
   TYPE:: injectGeneric
     INTEGER:: id
     CHARACTER(:), ALLOCATABLE:: name
     REAL(8):: vMod !Velocity (module)
     REAL(8):: T(1:3) !Temperature
-    REAL(8):: v(1:3) !Velocity(vector)
-    REAL(8):: vTh(1:3) !Thermal Velocity
     REAL(8):: n(1:3) !Direction of injection
     INTEGER:: nParticles !Number of particles to introduce each time step
     INTEGER:: sp !Species of injection
     INTEGER:: nEdges
     INTEGER, ALLOCATABLE:: edges(:) !Array with edges
+    TYPE(velDistCont):: v(1:3) !Velocity distribution function in each direction
     CONTAINS
       PROCEDURE, PASS:: init         => initInject
-      PROCEDURE, PASS:: addParticles => addParticlesMaxwellian
+      PROCEDURE, PASS:: addParticles
 
   END TYPE injectGeneric
 
@@ -64,9 +106,6 @@ MODULE moduleInject
       self%nParticles = self%nParticles * solver%pusher(sp)%every
       self%sp  = sp
 
-      self%v   = self%vMod * self%n
-      self%vTh = DSQRT(self%T/species(self%sp)%obj%m)
-
       !Gets the edge elements from which particles are injected
       !TODO: Improve this A LOT
       DO e = 1, mesh%numEdges
@@ -88,7 +127,7 @@ MODULE moduleInject
       END DO
       ! self%sumWeight = SUM(self%weight)
 
-    END SUBROUTINE
+    END SUBROUTINE initInject
 
     !Injection of particles
     SUBROUTINE doInjects()
@@ -114,12 +153,35 @@ MODULE moduleInject
 
     END SUBROUTINE doInjects
 
-    !Random velocity from maxwellian distribution
-    REAL(8) FUNCTION vBC(u, vth)
+    SUBROUTINE initVelDistMaxwellian(velDist, v, T, m)
+      IMPLICIT NONE
+
+      CLASS(velDistGeneric), ALLOCATABLE, INTENT(out):: velDist
+      REAL(8), INTENT(in):: v, T, m
+
+      velDist = velDistMaxwellian(v = v, vTh = DSQRT(T/m))
+
+    END SUBROUTINE initVelDistMaxwellian
+
+    SUBROUTINE initVelDistDelta(velDist, v)
+      IMPLICIT NONE
+
+      CLASS(velDistGeneric), ALLOCATABLE, INTENT(out):: velDist
+      REAL(8), INTENT(in):: v
+
+      velDist = velDistDelta(v = v)
+
+    END SUBROUTINE initVelDistDelta
+
+    !Random velocity from Maxwellian distribution
+    FUNCTION randomVelMaxwellian(self) RESULT (v)
       USE moduleConstParam, ONLY: PI
-      REAL(8), INTENT (in):: u, vth
+      IMPLICIT NONE
+
+      CLASS(velDistMaxwellian), INTENT(in):: self
+      REAL(8):: v
       REAL(8):: x, y
-      vBC=0.D0
+      v = 0.D0
       x = 0.D0
 
       DO WHILE (x == 0.D0)
@@ -127,11 +189,23 @@ MODULE moduleInject
       END DO
       CALL RANDOM_NUMBER(y)
 
-      vBC = u + vth*DSQRT(-2.D0*DLOG(x))*DCOS(2.D0*PI*y)
+      v = self%v + self%vTh*DSQRT(-2.D0*DLOG(x))*DCOS(2.D0*PI*y)
 
-    END FUNCTION vBC
+    END FUNCTION randomVelMaxwellian
 
-    SUBROUTINE addParticlesMaxwellian(self)
+    !Random velocity from Dirac's delta distribution
+    PURE FUNCTION randomVelDelta(self) RESULT(v)
+      IMPLICIT NONE
+
+      CLASS(velDistDelta), INTENT(in):: self
+      REAL(8):: v
+
+      v = self%v
+
+    END FUNCTION randomVelDelta
+
+    !Add particles for the injection
+    SUBROUTINE addParticles(self)
       USE moduleSpecies
       USE moduleSolver
       USE moduleMesh
@@ -185,9 +259,9 @@ MODULE moduleInject
 
         END IF
 
-        partInj(n)%v = (/ vBC(self%v(1), self%vTh(1)), &
-                          vBC(self%v(2), self%vTh(2)), &
-                          vBC(self%v(3), self%vTh(3)) /)
+        partInj(n)%v = (/ self%v(1)%obj%randomVel(), &
+                          self%v(2)%obj%randomVel(), &
+                          self%v(3)%obj%randomVel() /)
 
         !Push new particle
         CALL solver%pusher(self%sp)%pushParticle(partInj(n))
@@ -197,6 +271,6 @@ MODULE moduleInject
       END DO
       !$OMP END DO
 
-    END SUBROUTINE addParticlesMaxwellian
+    END SUBROUTINE addParticles
 
 END MODULE moduleInject