From ea8a0f661a3643c68f380ed28995873336eb2240 Mon Sep 17 00:00:00 2001
From: David A Minton <daminton@purdue.edu>
Date: Fri, 22 Oct 2021 02:53:33 -0400
Subject: [PATCH] Fixed broken sort

---
 src/encounter/encounter_check.f90 |  2 +-
 src/util/util_sort.f90            | 46 ++++++++++++++++++++-----------
 2 files changed, 31 insertions(+), 17 deletions(-)

diff --git a/src/encounter/encounter_check.f90 b/src/encounter/encounter_check.f90
index 4cc53d082..c64dbd68a 100644
--- a/src/encounter/encounter_check.f90
+++ b/src/encounter/encounter_check.f90
@@ -452,7 +452,7 @@ subroutine encounter_check_all_sort_and_sweep_plplm(nplm, nplt, xplm, vplm, xplt
 
          ntot_last = ntot
       end if
-     
+    
       !$omp parallel do default(private) schedule(static) &
       !$omp shared(xplm, xplt, vplm, vplt, rencm, renct, boundingbox) &
       !$omp firstprivate(dt, nplm, nplt, ntot)
diff --git a/src/util/util_sort.f90 b/src/util/util_sort.f90
index ca6e2d0e2..d27489da5 100644
--- a/src/util/util_sort.f90
+++ b/src/util/util_sort.f90
@@ -74,10 +74,14 @@ module pure subroutine util_sort_dp(arr)
       do i = 2, n
          tmp = arr(i)
          j = i - 1
-         do while ((j >= 1) .and. (arr(j) > tmp))
+         do while ((j > 1) .and. (arr(j) > tmp))
             arr(j + 1) = arr(j)
             j = j - 1
          end do
+         if ((j == 1) .and. (arr(j) > tmp)) then
+            arr(j + 1) = arr(j)
+            j = j - 1
+         end if
          arr(j + 1) = tmp
       end do
 
@@ -108,11 +112,14 @@ module pure subroutine util_sort_index_dp(arr, ind)
       do i = 2, n
          itmp = ind(i)
          j = i - 1
-         do while ((j >= 2) .and. (arr(ind(j)) > itmp))
+         do while ((j > 1) .and. (arr(ind(j)) > arr(itmp)))
             ind(j + 1) = ind(j)
             j = j - 1
          end do
-         if ((j == 1) .and. (arr(ind(1)) > itmp)) ind(2) = ind(1)
+         if ((j == 1) .and. (arr(ind(j)) > arr(itmp))) then
+            ind(j + 1) = ind(j)
+            j = j - 1
+         end if
          ind(j + 1) = itmp
       end do
 
@@ -137,10 +144,14 @@ module pure subroutine util_sort_i4b(arr)
       do i = 2, n
          tmp = arr(i)
          j = i - 1
-         do while ((j >= 1) .and. (arr(j) > tmp))
+         do while ((j > 1) .and. (arr(j) > tmp))
             arr(j + 1) = arr(j)
             j = j - 1
          end do
+         if ((j == 1) .and. (arr(j) > tmp)) then
+            arr(j + 1) = arr(j)
+            j = j - 1
+         end if
          arr(j + 1) = tmp
       end do
 
@@ -168,21 +179,17 @@ module pure subroutine util_sort_index_i4b(arr, ind)
          allocate(ind(n))
          ind = [(i, i=1, n)]
       end if
-
-      itmp = ind(2)
-      if (arr(ind(1)) > itmp) then
-         ind(2) = ind(1)
-         ind(1) = itmp
-      end if
-         
       do i = 2, n
          itmp = ind(i)
          j = i - 1
-         do while ((j >= 2) .and. (arr(ind(j)) > itmp))
+         do while ((j > 1) .and. (arr(ind(j)) > arr(itmp)))
             ind(j + 1) = ind(j)
             j = j - 1
          end do
-         if ((j == 1) .and. (arr(ind(1)) > itmp)) ind(2) = ind(1)
+         if ((j == 1) .and. (arr(ind(j)) > arr(itmp))) then
+            ind(j + 1) = ind(j)
+            j = j - 1
+         end if
          ind(j + 1) = itmp
       end do
 
@@ -207,10 +214,14 @@ module pure subroutine util_sort_sp(arr)
       do i = 2, n
          tmp = arr(i)
          j = i - 1
-         do while ((j >= 1) .and. (arr(j) > tmp))
+         do while ((j > 1) .and. (arr(j) > tmp))
             arr(j + 1) = arr(j)
             j = j - 1
          end do
+         if ((j == 1) .and. (arr(j) > tmp)) then
+            arr(j + 1) = arr(j)
+            j = j - 1
+         end if
          arr(j + 1) = tmp
       end do
 
@@ -241,11 +252,14 @@ module pure subroutine util_sort_index_sp(arr, ind)
       do i = 2, n
          itmp = ind(i)
          j = i - 1
-         do while ((j >= 2) .and. (arr(ind(j)) > itmp))
+         do while ((j > 1) .and. (arr(ind(j)) > arr(itmp)))
             ind(j + 1) = ind(j)
             j = j - 1
          end do
-         if ((j == 1) .and. (arr(ind(1)) > itmp)) ind(2) = ind(1)
+         if ((j == 1) .and. (arr(ind(j)) > arr(itmp))) then
+            ind(j + 1) = ind(j)
+            j = j - 1
+         end if
          ind(j + 1) = itmp
       end do