From b436537edfed991e6ff560a1d1b2d4b018507db1 Mon Sep 17 00:00:00 2001
From: Michael Jarrett <mjarrett@terrapower.com>
Date: Fri, 4 Oct 2024 09:32:26 -0700
Subject: [PATCH] Improving the robustness of  HexBlock._rotatePins() (#1859)

---
 armi/reactor/blocks.py | 14 ++++++++------
 doc/release/0.4.rst    |  1 +
 2 files changed, 9 insertions(+), 6 deletions(-)

diff --git a/armi/reactor/blocks.py b/armi/reactor/blocks.py
index bef0ade54..cc18826a0 100644
--- a/armi/reactor/blocks.py
+++ b/armi/reactor/blocks.py
@@ -2136,10 +2136,12 @@ def _rotatePins(self, rotNum, justCompute=False):
                 "Cannot rotate {0} to rotNum {1}. Must be 0-5. ".format(self, rotNum)
             )
 
-        # Pin numbers start at 1. Number of pins in the block is assumed to be based on
-        # cladding count.
-        numPins = self.getNumComponents(Flags.CLAD)
-        rotateIndexLookup = dict(zip(range(1, numPins + 1), range(1, numPins + 1)))
+        numPins = self.getNumPins()
+        hexRings = hexagon.numRingsToHoldNumCells(numPins)
+        fullNumPins = hexagon.totalPositionsUpToRing(hexRings)
+        rotateIndexLookup = dict(
+            zip(range(1, fullNumPins + 1), range(1, fullNumPins + 1))
+        )
 
         # Look up the current orientation and add this to it. The math below just rotates
         # from the reference point so we need a total rotation.
@@ -2147,7 +2149,7 @@ def _rotatePins(self, rotNum, justCompute=False):
 
         # non-trivial rotation requested
         # start at 2 because pin 1 never changes (it's in the center!)
-        for pinNum in range(2, numPins + 1):
+        for pinNum in range(2, fullNumPins + 1):
             if rotNum == 0:
                 # Rotation to reference orientation. Pin locations are pin IDs.
                 pass
@@ -2162,7 +2164,7 @@ def _rotatePins(self, rotNum, justCompute=False):
         if not justCompute:
             self.setRotationNum(rotNum)
             self.p["pinLocation"] = [
-                rotateIndexLookup[pinNum] for pinNum in range(1, numPins + 1)
+                rotateIndexLookup[pinNum] for pinNum in range(1, fullNumPins + 1)
             ]
 
         return rotateIndexLookup
diff --git a/doc/release/0.4.rst b/doc/release/0.4.rst
index d2374817f..973d91cf0 100644
--- a/doc/release/0.4.rst
+++ b/doc/release/0.4.rst
@@ -12,6 +12,7 @@ New Features
 #. Removing the ``tabulate`` dependency by ingesting it to ``armi.utils.tabulate``. (`PR#1811 <https://github.com/terrapower/armi/pull/1811>`_)
 #. Adding ``--skip-inspection`` flag to ``CompareCases`` CLI. (`PR#1842 <https://github.com/terrapower/armi/pull/1842>`_)
 #. Allow merging a component with zero area into another component (`PR#1858 <https://github.com/terrapower/armi/pull/1858>`_)
+#. Use ``Block.getNumPins()`` in ``HexBlock._rotatePins()``. (`PR#1859 <https://github.com/terrapower/armi/pull/1859>`_)
 #. Provide utilities for determining location of a rotated object in a hexagonal lattice (``getIndexOfRotatedCell``). (`PR#1846 <https://github.com/terrapower/armi/1846`)
 #. Allow merging a component with zero area into another component. (`PR#1858 <https://github.com/terrapower/armi/pull/1858>`_)
 #. Provide ``Parameter.hasCategory`` for quickly checking if a parameter is defined with a given category. (`PR#1899 <https://github.com/terrapower/armi/pull/1899>`_)