Final implementation of ionization process by electron impact.

Possibility to input initial species distributions (density, velocity
    and temperature) via an input file for each species.

New moduleRandom includes function to generate random numbers in
different ways (still uses) the implicit RANDOM_NUMBER().

src/modules/mesh/1DCart/moduleMesh1DCart.f90

@@ -23,7 +23,7 @@ MODULE moduleMesh1DCart
     CONTAINS
       PROCEDURE, PASS:: init     => initEdge1DCart
       PROCEDURE, PASS:: getNodes => getNodes1DCart
-      PROCEDURE, PASS:: randPos  => randPos1DCart
+      PROCEDURE, PASS:: randPos  => randPosEdge
 
   END TYPE meshEdge1DCart
 
@@ -110,6 +110,7 @@ MODULE moduleMesh1DCart
     REAL(8):: arNodes(1:2)
     CONTAINS
       PROCEDURE, PASS::   init        => initVol1DCartSegm
+      PROCEDURE, PASS::   randPos     => randPos1DCartSeg
       PROCEDURE, PASS::   area        => areaSegm
       PROCEDURE, NOPASS:: fPsi        => fPsiSegm
       PROCEDURE, NOPASS:: dPsi        => dPsiSegm
@@ -226,13 +227,13 @@ MODULE moduleMesh1DCart
     END FUNCTION getNodes1DCart
 
     !Calculates a 'random' position in edge
-    FUNCTION randPos1DCart(self) RESULT(r)
+    FUNCTION randPosEdge(self) RESULT(r)
       CLASS(meshEdge1DCart), INTENT(in):: self
       REAL(8):: r(1:3)
 
       r = (/ self%x, 0.D0, 0.D0 /)
 
-    END FUNCTION randPos1DCart
+    END FUNCTION randPosEdge
 
     !VOLUME FUNCTIONS
     !SEGMENT FUNCTIONS
@@ -265,6 +266,24 @@ MODULE moduleMesh1DCart
 
     END SUBROUTINE initVol1DCartSegm
 
+    !Calculates a random position in 1D volume
+    FUNCTION randPos1DCartSeg(self) RESULT(r)
+      USE moduleRandom
+      IMPLICIT NONE
+
+      CLASS(meshVol1DCartSegm), INTENT(in):: self
+      REAL(8):: r(1:3)
+      REAL(8):: xii(1:3)
+      REAL(8), ALLOCATABLE:: fPsi(:)
+
+      xii(1)   = random(-1.D0, 1.D0)
+      xii(2:3) = 0.D0
+
+      fPsi = self%fPsi(xii)
+      r(1) = DOT_PRODUCT(fPsi, self%x)
+
+    END FUNCTION randPos1DCartSeg
+
     !Computes element area
     PURE SUBROUTINE areaSegm(self)
       IMPLICIT NONE
@@ -479,6 +498,7 @@ MODULE moduleMesh1DCart
     END SUBROUTINE nextElementSegm
 
     !COMMON FUNCTIONS FOR 1D VOLUME ELEMENTS
+    !Calculates a random position in 1D volume
     !Computes the element Jacobian determinant
     PURE FUNCTION detJ1DCart(self, xi, dPsi_in) RESULT(dJ)
       IMPLICIT NONE