From 52ecd98a11fc4f459c9bd0b59cb854ff402eeb08 Mon Sep 17 00:00:00 2001
From: Joshua Larsen <jlarsen@usgs.gov>
Date: Fri, 10 Apr 2020 14:13:08 -0700
Subject: [PATCH] =?UTF-8?q?Fix(ModflowDis):=20zero=20based=20get=5Fnode()?=
 =?UTF-8?q?=20and=20get=5Flrc()=E2=80=A6=20(#847)?=
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* Fix(ModflowDis): zero based get_node() and get_lrc() for input parameters and output

* added test_get_lrc_get_node()
---
 autotest/t007_test.py  | 13 +++++++++++++
 flopy/modflow/mfdis.py | 10 ++++++----
 2 files changed, 19 insertions(+), 4 deletions(-)

diff --git a/autotest/t007_test.py b/autotest/t007_test.py
index 1e24b8146..a02324f7e 100644
--- a/autotest/t007_test.py
+++ b/autotest/t007_test.py
@@ -1367,6 +1367,19 @@ def test_get_vertices():
     assert np.array_equal(a1, a2)
 
 
+def test_get_lrc_get_node():
+    node = 50
+    ml = flopy.modflow.Modflow()
+    dis = flopy.modflow.ModflowDis(ml, nlay=1, nrow=1, ncol=201, delr=10,
+                                   delc=1, top=50, botm=0)
+    lrc = dis.get_lrc([node, ])
+    if lrc[0] != (0, 0, 50):
+        raise AssertionError("get_lrc() is not returning zero based (k, i, j)")
+    nodes = dis.get_node(lrc)
+    if nodes[0] != node:
+        raise AssertionError('get_node() is not returning zero based node')
+
+
 def test_vertex_model_dot_plot():
     import matplotlib.pyplot as plt
     # load up the vertex example problem
diff --git a/flopy/modflow/mfdis.py b/flopy/modflow/mfdis.py
index dbdc3d2f5..8f36524b4 100644
--- a/flopy/modflow/mfdis.py
+++ b/flopy/modflow/mfdis.py
@@ -479,7 +479,8 @@ def get_rc_from_node_coordinates(self, x, y, local=True):
 
     def get_lrc(self, nodes):
         """
-        Get layer, row, column from a list of MODFLOW node numbers.
+        Get layer, row, column from a list of zero based
+        MODFLOW node numbers.
 
         Returns
         -------
@@ -491,7 +492,7 @@ def get_lrc(self, nodes):
         nrc = self.nrow * self.ncol
         v = []
         for node in nodes:
-            k = int(node / nrc)
+            k = int((node + 1) / nrc)
             if (k * nrc) < node:
                 k += 1
             ij = int(node - (k - 1) * nrc)
@@ -499,12 +500,13 @@ def get_lrc(self, nodes):
             if (i * self.ncol) < ij:
                 i += 1
             j = ij - (i - 1) * self.ncol
-            v.append((k, i, j))
+            v.append((k - 1, i - 1, j))
         return v
 
     def get_node(self, lrc_list):
         """
-        Get node number from a list of MODFLOW layer, row, column tuples.
+        Get node number from a list of zero based MODFLOW
+        layer, row, column tuples.
 
         Returns
         -------