From 7999e74388e1760f95420e1886efe32cf3ec6516 Mon Sep 17 00:00:00 2001
From: Aaron LI <aly@aaronly.me>
Date: Wed, 25 Oct 2017 21:02:32 +0800
Subject: clusters/solver: Update buffer_np description and handling

---
 fg21sim/extragalactic/clusters/halo.py   |  2 ++
 fg21sim/extragalactic/clusters/solver.py | 13 +++++++++----
 2 files changed, 11 insertions(+), 4 deletions(-)

(limited to 'fg21sim/extragalactic/clusters')

diff --git a/fg21sim/extragalactic/clusters/halo.py b/fg21sim/extragalactic/clusters/halo.py
index 281093d..6b91f7f 100644
--- a/fg21sim/extragalactic/clusters/halo.py
+++ b/fg21sim/extragalactic/clusters/halo.py
@@ -149,6 +149,8 @@ class RadioHalo:
         self.gamma_max = self.configs.getn(comp+"/gamma_max")
         self.gamma_np = self.configs.getn(comp+"/gamma_np")
         self.buffer_np = self.configs.getn(comp+"/buffer_np")
+        if self.buffer_np == 0:
+            self.buffer_np = None
         self.time_step = self.configs.getn(comp+"/time_step")
         self.time_init = self.configs.getn(comp+"/time_init")
         self.injection_index = self.configs.getn(comp+"/injection_index")
diff --git a/fg21sim/extragalactic/clusters/solver.py b/fg21sim/extragalactic/clusters/solver.py
index 52e07c7..ad5c320 100644
--- a/fg21sim/extragalactic/clusters/solver.py
+++ b/fg21sim/extragalactic/clusters/solver.py
@@ -109,10 +109,12 @@ class FokkerPlanckSolver:
     f_escape : function, optional
         Function f(x,t) to calculate the escape coefficient T(x,t)
     buffer_np : int, optional
-        Number of grid points taking as the buffer region near the lower
-        boundary.  The densities within this buffer region will be replaced
-        by extrapolating an power law to avoid unphysical accumulations.
-        This fix is ignored if this parameter is not specified.
+        Number of grid cells taken as the buffer regions near both the
+        lower and upper boundaries.  The values within the buffer regions
+        will be replaced by extrapolating with a power law to avoid
+        unphysical pile-ups.
+        The fix will be ignored if this parameter is ``None`` or is less
+        than 2.
         (This parameter is suggested to be about 5%-10% of ``x_np``.)
 
     NOTE
@@ -142,6 +144,9 @@ class FokkerPlanckSolver:
         self.f_injection = f_injection
         self.f_escape = f_escape
         self.buffer_np = buffer_np
+        if (buffer_np is not None) and (buffer_np < 2):
+            logger.warning("buffer_np set but < 2; disable boundary fixes!")
+            self.buffer_np = None
 
     @property
     def x(self):
-- 
cgit v1.2.2