Index: /branches/eam_branches/ipp-20230313/Ohana/src/opihi/lib.data/spline.c
===================================================================
--- /branches/eam_branches/ipp-20230313/Ohana/src/opihi/lib.data/spline.c	(revision 42681)
+++ /branches/eam_branches/ipp-20230313/Ohana/src/opihi/lib.data/spline.c	(revision 42682)
@@ -113,7 +113,19 @@
   opihi_flt dx, a, b, value;
   
-  // saturate correction at high and low ends
-  if (X < x[0]) return y[0];
-  if (X > x[N-1]) return y[N-1];
+  // linear extrapolation past endpoints
+  if (X < x[0]) {
+    hi = 1;
+    lo = 0;
+    goto evaluate;
+    // alternative: saturate correction at high and low ends
+    // return y[0]; 
+  }
+  if (X > x[N-1]) {
+    hi = N - 1;
+    lo = N - 2;
+    goto evaluate;
+    // alternative: saturate correction at high and low ends
+    // return y[N-1];
+  }
 
   /* find correct element in array (x must be sorted) */
@@ -128,4 +140,6 @@
     }
   }
+
+evaluate:
 
   /* error condition: duplicate abssisca */