Index: trunk/Ohana/src/opihi/cmd.data/test/gaussj.sh
===================================================================
--- trunk/Ohana/src/opihi/cmd.data/test/gaussj.sh	(revision 16139)
+++ trunk/Ohana/src/opihi/cmd.data/test/gaussj.sh	(revision 16269)
@@ -243,2 +243,52 @@
 end
 
+# a very large matrix equation
+# timing on my laptop: 100 : ~1sec; 300 : ~7sec; 1000 : ~88sec
+# note: at Ndim = 1000, it failed (Ax - B was in the range -2..+2)
+macro test6
+ if ($0 != 2)
+  echo "USAGE: test6 (Ndim)"
+  break
+ end
+
+ $PASS = 1
+ break -auto off
+
+ $Ndim = $1
+ mcreate A $Ndim $Ndim
+ create B 0 $Ndim
+
+ # generate the diagonal + off-diagonal elements
+ for i 0 $Ndim
+   A[$i][$i] = 2.0
+   if ($i > 0)
+     A[$i][$i-1] = -1.0
+   end
+   if ($i < $Ndim - 1)
+     A[$i][$i+1] = -1.0
+   end
+ end
+
+ set inB = B
+ set inA = A
+
+ gaussj A B
+ if (not($STATUS))
+   $PASS = 0
+ end
+
+ set meas = zero(inB)
+ for i 0 B[]
+  for j 0 B[]
+   meas[$i] = meas[$i] + inA[$i][$j] * B[$j]
+  end
+ end
+
+ for i 0 inB[]
+  if (abs(inB[$i]-meas[$i]) > 1e-3)
+    $PASS = 0
+    echo inB[$i] meas[$i] {inB[$i]-meas[$i]}
+  end
+ end
+end
+