CDE

Task/Conditional-structures/Fortran/conditional-structures-1.f

@@ -0,0 +1,7 @@
+if ( a .gt. 20.0 ) then
+   q = q + a**2
+else if ( a .ge. 0.0 ) then
+   q = q + 2*a**3
+else
+   q = q - a
+end if

Task/Conditional-structures/Fortran/conditional-structures-2.f

@@ -0,0 +1,8 @@
+select case (i)
+   case (21:)      ! matches all integers greater than 20
+      q = q + i**2
+   case (0:20)     ! matches all integers between 0 and 20 (inclusive)
+      q = q + 2*i**3
+   case default    ! matches all other integers (negative in this particular case)
+      q = q - I
+end select

Task/Conditional-structures/Fortran/conditional-structures-3.f

@@ -0,0 +1,31 @@
+! diffusion grid time step
+where     (edge_type(1:n,1:m) == center)
+   anew(1:n,1:m) = (a(1:n,1:m) + a(0:n-1,1:m) + a(2:n+1,1:m) + a(1:n,0:m-1) + a(1:n,2:m+1)) / 5
+
+elsewhere (edge_type(1:n,1:m) == left)
+   anew(1:n,1:m) = (a(1:n,1:m) + 2*a(2:n+1,1:m) + a(1:n,0:m-1) + a(1:n,2:m+1)) / 5
+
+elsewhere (edge_type(1:n,1:m) == right)
+   anew(1:n,1:m) = (a(1:n,1:m) + 2*a(0:n-1,1:m) + a(1:n,0:m-1) + a(1:n,2:m+1)) / 5
+
+elsewhere (edge_type(1:n,1:m) == top)
+   anew(1:n,1:m) = (a(1:n,1:m) + a(0:n-1,1:m) + a(2:n+1,1:m) + 2*a(1:n,2:m+1)) / 5
+
+elsewhere (edge_type(1:n,1:m) == bottom)
+   anew(1:n,1:m) = (a(1:n,1:m) + a(0:n-1,1:m) + a(2:n+1,1:m) + 2*a(1:n,0:m-1)) / 5
+
+elsewhere (edge_type(1:n,1:m) == left_top)
+   anew(1:n,1:m) = (a(1:n,1:m) + 2*a(2:n+1,1:m) + 2*a(1:n,2:m+1)) / 5
+
+elsewhere (edge_type(1:n,1:m) == right_top)
+   anew(1:n,1:m) = (a(1:n,1:m) + 2*a(0:n-1,1:m) + 2*a(1:n,2:m+1)) / 5
+
+elsewhere (edge_type(1:n,1:m) == left_bottom)
+   anew(1:n,1:m) = (a(1:n,1:m) + 2*a(2:n+1,1:m) + 2*a(1:n,0:m-1)) / 5
+
+elsewhere (edge_type(1:n,1:m) == right_bottom)
+   anew(1:n,1:m) = (a(1:n,1:m) + 2*a(0:n-1,1:m) + 2*a(1:n,0:m-1)) / 5
+
+elsewhere      ! sink/source, does not change
+   anew(1:n,1:m) = a(1:n,1:m)
+end where