diff --git a/python/swiftest/swiftest/init_cond.py b/python/swiftest/swiftest/init_cond.py
index 8dcf08cf2..02ff6f8e1 100644
--- a/python/swiftest/swiftest/init_cond.py
+++ b/python/swiftest/swiftest/init_cond.py
@@ -285,8 +285,8 @@ def vec2xr(param: Dict, **kwargs: Any):
     if param['ROTATION']:
         if "rot" not in kwargs and "Gmass" in kwargs:
             kwargs['rot'] = np.zeros((len(kwargs['Gmass']),3))
-        if "Ip" not in kwargs and "rot" in kwargs:
-            kwargs['Ip'] = np.full_like(kwargs['rot'], 0.4)
+        if "Ip" not in kwargs and "Gmass" in kwargs:
+            kwargs['Ip'] = np.full_like(kwargs['Gmass'], 0.4)
 
     if "time" not in kwargs:
         kwargs["time"] = np.array([0.0])
diff --git a/src/swiftest/swiftest_io.f90 b/src/swiftest/swiftest_io.f90
index fe4ecba18..8ae50ba2d 100644
--- a/src/swiftest/swiftest_io.f90
+++ b/src/swiftest/swiftest_io.f90
@@ -2094,7 +2094,6 @@ module subroutine swiftest_io_param_reader(self, unit, iotype, v_list, iostat, i
             return
          end if
 
-
          if ((param%collision_model /= "MERGE")       .and. &
              (param%collision_model /= "BOUNCE")    .and. &
              (param%collision_model /= "FRAGGLE")) then
@@ -2127,7 +2126,6 @@ module subroutine swiftest_io_param_reader(self, unit, iotype, v_list, iostat, i
             param%inv_c2 = (param%inv_c2)**(-2)
          end if
 
-
          select case(trim(adjustl(param%interaction_loops)))
          case("ADAPTIVE")
             param%ladaptive_interactions = .true.
@@ -2230,6 +2228,7 @@ module subroutine swiftest_io_param_writer(self, unit, iotype, v_list, iostat, i
       character(*),parameter :: Ifmt  = '(I0)'         !! Format label for integer values
       character(*),parameter :: Rfmt  = '(ES25.17)'    !! Format label for real values 
       character(*),parameter :: Lfmt  = '(L1)'         !! Format label for logical values 
+      integer(I4B)                   :: nseeds
 
       associate(param => self)
          call io_param_writer_one("T0", param%t0, unit)
@@ -2275,6 +2274,7 @@ module subroutine swiftest_io_param_writer(self, unit, iotype, v_list, iostat, i
          call io_param_writer_one("INTERACTION_LOOPS", param%interaction_loops, unit)
          call io_param_writer_one("ENCOUNTER_CHECK_PLPL", param%encounter_check_plpl, unit)
          call io_param_writer_one("ENCOUNTER_CHECK_PLTP", param%encounter_check_pltp, unit)
+         call io_param_writer_one("ENCOUNTER_SAVE", param%encounter_save, unit)
 
          if (param%lenergy) then
             call io_param_writer_one("FIRSTENERGY", param%lfirstenergy, unit)
@@ -2282,6 +2282,14 @@ module subroutine swiftest_io_param_writer(self, unit, iotype, v_list, iostat, i
          call io_param_writer_one("FIRSTKICK",param%lfirstkick, unit)
          call io_param_writer_one("MAXID",param%maxid, unit)
          call io_param_writer_one("MAXID_COLLISION",param%maxid_collision, unit)
+
+         if (param%GMTINY > 0.0_DP) call io_param_writer_one("GMTINY",param%GMTINY, unit)
+         if (param%min_GMfrag > 0.0_DP) call io_param_writer_one("MIN_GMFRAG",param%min_GMfrag, unit)
+         call io_param_writer_one("COLLISION_MODEL",param%collision_model, unit)
+         if (param%collision_model == "FRAGGLE" ) then
+            nseeds = size(param%seed)
+            call io_param_writer_one("SEED", [nseeds, param%seed(:)], unit)
+         end if
    
          iostat = 0
          iomsg = "UDIO not implemented"
@@ -2837,7 +2845,6 @@ module subroutine swiftest_io_toupper(string)
    end subroutine swiftest_io_toupper
 
 
-
    module subroutine swiftest_io_write_discard(self, param)
       !! author: David A. Minton
       !!