Changes between Version 34 and Version 35 of ModulesOnAstroBear

Timestamp:

01/14/13 21:26:42 (13 years ago)

Author:

Jonathan

Comment:

—

ModulesOnAstroBear

@@ -201 +201 @@
 Initializing a grid  involves taking a spatially-constructed problem setup and discretizing it so that it fits nicely in an array.  This process is easiest to explain by dissecting an example, such as the one below, where we are trying to initialize the grid with a uniform background and an overdense spherical clump centered at the origin with radius 1.
 
-Note that during the !ProblemGridInit routine, ghost zones do not need to be initialized (rmbc = 0) - however - during beforestep calculations they should be.
-
-{{{
-
-    rmbc=levels(Info%level)%gmbc(levels(Info%level)%step)
-
-    mx=Info%mX(1); dx=levels(Info%level)%dX; xlower=Info%xbounds(1,1)
-    my=Info%mX(2);                           ylower=Info%xbounds(2,1)
-    mz=Info%mX(3);                           zlower=Info%xbounds(3,1)
-
-    SELECT CASE(nDim)
-    CASE(2)
-       zrmbc=0;mz=1;zl=0;dz=0
-    CASE(3)
-       zrmbc=rmbc
-    END SELECT
-
-    ! Initialize environment
-    DO k=1-zrmbc, mz+zrmbc
-        DO j=1-rmbc, my+rmbc
-            DO i=1-rmbc, mx+rmbc
-
-                x=(xlower + (REAL(i, xPrec)-half) * dx)
-                y=(ylower + (REAL(j, xPrec)-half) * dx)
-                z=(zlower + (REAL(k, xPrec)-half) * dx)
-
-                Info%q(i,j,k,irho) = rho(x,y,z)
-            END DO
+Note that during the !ProblemGridInit routine, ghost zones do not need to be initialized (rmbc = 0) - however - during beforestep calculations they should be (if needed).
+
+{{{
+  SUBROUTINE ProblemGridInit(Info)
+    TYPE(InfoDef), POINTER :: Info
+    INTEGER :: i,j,k
+    REAL(KIND=xPREC) :: pos(3)
+
+    ! Initialize background
+    Info%q(1:Info%mX(1),1:Info%mX(2),1:Info%mX(3), 1)=1d0
+    Info%q(1:Info%mX(1),1:Info%mX(2),1:Info%mX(3), ivx)=0d0
+    IF (ivy /= 0) Info%q(1:Info%mX(1),1:Info%mX(2),1:Info%mX(3), ivy)=0d0
+    IF (ivz /= 0) Info%q(1:Info%mX(1),1:Info%mX(2),1:Info%mX(3), ivz)=0d0
+    IF (iE /= 0) Info%q(1:Info%mX(1),1:Info%mX(2),1:Info%mX(3), iE)=gamma7    
+
+    ! Increase density for points inside of clump
+    DO i=1, Info%mX(1)
+      DO j=1, Info%mX(2)
+        DO k=1, Info%mX(3)
+          pos=CellPos(Info, i, j, k)
+          IF (sqrt(sum(pos**2)) < 1d0) THEN
+            Info%q(i,j,k,irho) = 10d0
+          END IF                  
         END DO
+      END DO
     END DO
-}}}
+  END SUBROUTINE
+}}}
+
+Now let's say we want to be able to adjust the density of the clump and the radius of the clump at run-time.  To do this we need to declare two variables within our module..
+
+{{{
+MODULE Problem
+  USE GlobalDeclarations
+  USE PhysicsDeclarations
+  USE DataDeclarations
+  IMPLICIT NONE
+  SAVE
+  PUBLIC ProblemModuleInit, ProblemGridInit, &
+       ProblemBeforeStep, ProblemAfterStep, ProblemSetErrFlag, ProblemBeforeGlobalStep
+  PRIVATE REAL(KIND=qPREC) :: rho, radius
+
+CONTAINS
+
+  SUBROUTINE ProblemModuleInit()
+    NAMELIST/ProblemData/ rho, radius
+    OPEN(UNIT=PROBLEM_DATA_HANDLE, FILE='problem.data', STATUS="OLD")
+    READ(PROBLEM_DATA_HANDLE,NML=ProblemData)
+    CLOSE(PROBLEM_DATA_HANDLE)
+  END SUBROUTINE
+  
+  SUBROUTINE ProblemGridInit(Info)
+    TYPE(InfoDef), POINTER :: Info
+    INTEGER :: i,j,k
+    REAL(KIND=xPREC) :: pos(3)
+
+    ! Initialize background
+    Info%q(1:Info%mX(1),1:Info%mX(2),1:Info%mX(3), 1)=1d0
+    Info%q(1:Info%mX(1),1:Info%mX(2),1:Info%mX(3), ivx)=0d0
+    IF (ivy /= 0) Info%q(1:Info%mX(1),1:Info%mX(2),1:Info%mX(3), ivy)=0d0
+    IF (ivz /= 0) Info%q(1:Info%mX(1),1:Info%mX(2),1:Info%mX(3), ivz)=0d0
+    IF (iE /= 0) Info%q(1:Info%mX(1),1:Info%mX(2),1:Info%mX(3), iE)=gamma7    
+
+    ! Increase density for points inside of clump
+    DO i=1, Info%mX(1)
+      DO j=1, Info%mX(2)
+        DO k=1, Info%mX(3)
+          pos=CellPos(Info, i, j, k)
+          IF (sqrt(sum(pos**2)) < radius) THEN
+            Info%q(i,j,k,irho) = rho
+          END IF                  
+        END DO
+      END DO
+    END DO
+  END SUBROUTINE
+}}}
+
+
+
 
 Each grid (or {{{InfoDef}}} structure) comes with several arrays that describe its geometry: