diff --git a/test/studies/sinLUT/PREDIFF b/test/studies/sinLUT/PREDIFF
new file mode 100755
index 000000000000..f396dcd4ee8b
--- /dev/null
+++ b/test/studies/sinLUT/PREDIFF
@@ -0,0 +1,23 @@
+#!/usr/bin/env bash
+
+cp $2 $2.prediff.tmp
+> $2
+
+# check that Chapel Calculated == Chapel Lookup
+calc=`sed '1q;d' $2.prediff.tmp | sed 's/.*: //'`
+lookup=`sed '2q;d' $2.prediff.tmp | sed 's/.*: //'`
+if [ "$calc" = "$lookup" ]; then
+    echo "Chapel Calculated == Chapel Lookup" >> $2
+else
+    echo "Chapel Calculated != Chapel Lookup" >> $2
+fi
+# check that C Caclulated == C Lookup
+calc=`sed '3q;d' $2.prediff.tmp | sed 's/.*: //'`
+lookup=`sed '4q;d' $2.prediff.tmp | sed 's/.*: //'`
+if [ "$calc" = "$lookup" ]; then
+    echo "C Calculated == C Lookup" >> $2
+else
+    echo "C Calculated != C Lookup" >> $2
+fi
+
+rm $2.prediff.tmp
diff --git a/test/studies/sinLUT/c_sin.c b/test/studies/sinLUT/c_sin.c
index 654395d6b883..026f51f51d5c 100644
--- a/test/studies/sinLUT/c_sin.c
+++ b/test/studies/sinLUT/c_sin.c
@@ -2,16 +2,14 @@
 #include <stdio.h>
 #include <math.h>
 #include <stdlib.h>
-#include <time.h>
 
 #include "c_sin.h"
 
 static float table[256];
 
-float c_sin(unsigned int size, int iterations, float* resArray)
+float c_sin(unsigned int size, int iterations, unsigned int seed, float* resArray)
 {
-	  time_t t;
-	  srand((unsigned )time(&t));
+	  srand(seed);
 
     for (int i=0; i < iterations; i++)
 	  {
@@ -28,11 +26,10 @@ void fillTable(unsigned int size)
         table[i] = sin(2.0 * 3.1415927 * (float) i / (float) size);
 }
 
-float c_table(unsigned int size, int iterations, float* resArray)
+float c_table(unsigned int size, int iterations, unsigned int seed, float* resArray)
 {
-	  time_t t;
     fillTable(size);
-    srand((unsigned )time(&t));
+    srand(seed);
 
     for (int i=0; i < iterations; i++)
     {
diff --git a/test/studies/sinLUT/c_sin.h b/test/studies/sinLUT/c_sin.h
index 055d6ef1b75b..ce495ce13ec4 100644
--- a/test/studies/sinLUT/c_sin.h
+++ b/test/studies/sinLUT/c_sin.h
@@ -1,4 +1,4 @@
-float c_sin(unsigned int size, int iterations, float* resArray);
+float c_sin(unsigned int size, int iterations, unsigned int seed, float* resArray);
 void fillTable(unsigned int size);
-float c_table(unsigned int size, int iterations, float* resArray);
+float c_table(unsigned int size, int iterations, unsigned int seed, float* resArray);
 
diff --git a/test/studies/sinLUT/chplSin.chpl b/test/studies/sinLUT/chplSin.chpl
index a748a06968a9..0ca22d0e3afb 100644
--- a/test/studies/sinLUT/chplSin.chpl
+++ b/test/studies/sinLUT/chplSin.chpl
@@ -4,11 +4,17 @@ use Time;
 use Math;
 use CTypes;
 
-config const seed = 314159;
+config const seed: uint(32) = 314159;
 config const correctness = false;
 
-extern proc c_sin(size: uint(32), iterations: int(32), resArray: c_ptr(real(32))): real(32);
-extern proc c_table(size: uint(32), iterations: int(32), resArray: c_ptr(real(32))): real(32);
+extern proc c_sin(size: uint(32),
+                  iterations: int(32),
+                  seed: uint(32),
+                  resArray: c_ptr(real(32))): real(32);
+extern proc c_table(size: uint(32),
+                    iterations: int(32),
+                    seed: uint(32),
+                    resArray: c_ptr(real(32))): real(32);
 
 proc sin_calc(size: uint(32), iterations : int(32)): real(32) {
 
@@ -76,7 +82,7 @@ proc main()
     var resArray = allocate(real(32), iterations);
 
     c_calc.start();
-    var c_calc_res = c_sin(size, iterations, resArray);
+    var c_calc_res = c_sin(size, iterations, seed, resArray);
     c_calc.stop();
     write("C Calculated: ");
     if correctness
@@ -84,7 +90,7 @@ proc main()
       else writeln(c_calc.elapsed(), " seconds");
 
     c_lookup.start();
-    var table_calc_res = c_table(size, iterations, resArray);
+    var table_calc_res = c_table(size, iterations, seed, resArray);
     c_lookup.stop();
     write("C Lookup: ");
     if correctness
diff --git a/test/studies/sinLUT/chplSin.good b/test/studies/sinLUT/chplSin.good
index ae73c1548c6a..b3da301ebcb9 100644
--- a/test/studies/sinLUT/chplSin.good
+++ b/test/studies/sinLUT/chplSin.good
@@ -1,4 +1,2 @@
-Chapel Calculated: -1.2311
-Chapel Lookup: -1.2311
-C Calculated: -1.2311
-C Lookup: -1.2311
+Chapel Calculated == Chapel Lookup
+C Calculated == C Lookup
diff --git a/test/studies/sinLUT/chplSinBlock.chpl b/test/studies/sinLUT/chplSinBlock.chpl
index cd1bb367806c..9b5879934e78 100644
--- a/test/studies/sinLUT/chplSinBlock.chpl
+++ b/test/studies/sinLUT/chplSinBlock.chpl
@@ -5,11 +5,17 @@ use Math;
 use CTypes;
 use BlockDist;
 
-config const seed = 314159;
+config const seed: uint(32) = 314159;
 config const correctness = false;
 
-extern proc c_sin(size: uint(32), iterations: int(32), resArray: c_ptr(real(32))): real(32);
-extern proc c_table(size: uint(32), iterations: int(32), resArray: c_ptr(real(32))): real(32);
+extern proc c_sin(size: uint(32),
+                  iterations: int(32),
+                  seed: uint(32),
+                  resArray: c_ptr(real(32))): real(32);
+extern proc c_table(size: uint(32),
+                    iterations: int(32),
+                    seed: uint(32),
+                    resArray: c_ptr(real(32))): real(32);
 
 proc sin_calc(size: uint(32), iterations : int(32)): real(32) {
 
@@ -115,7 +121,7 @@ proc main()
     var resArray = allocate(real(32), iterations);
 
     c_calc.start();
-    var c_calc_res = c_sin(size, iterations, resArray);
+    var c_calc_res = c_sin(size, iterations, seed, resArray);
     c_calc.stop();
     write("C Calculated: ");
     if correctness
@@ -123,7 +129,7 @@ proc main()
       else writeln(c_calc.elapsed(), " seconds");
 
     c_lookup.start();
-    var table_calc_res = c_table(size, iterations, resArray);
+    var table_calc_res = c_table(size, iterations, seed, resArray);
     c_lookup.stop();
     write("C Lookup: ");
     if correctness
diff --git a/test/studies/sinLUT/chplSinBlock.good b/test/studies/sinLUT/chplSinBlock.good
index ae73c1548c6a..b3da301ebcb9 100644
--- a/test/studies/sinLUT/chplSinBlock.good
+++ b/test/studies/sinLUT/chplSinBlock.good
@@ -1,4 +1,2 @@
-Chapel Calculated: -1.2311
-Chapel Lookup: -1.2311
-C Calculated: -1.2311
-C Lookup: -1.2311
+Chapel Calculated == Chapel Lookup
+C Calculated == C Lookup
diff --git a/test/studies/sinLUT/chplSinReplicated.chpl b/test/studies/sinLUT/chplSinReplicated.chpl
index 799170ec001e..a262d87ed0b2 100644
--- a/test/studies/sinLUT/chplSinReplicated.chpl
+++ b/test/studies/sinLUT/chplSinReplicated.chpl
@@ -5,11 +5,17 @@ use Math;
 use CTypes;
 use ReplicatedDist;
 
-config const seed = 314159;
+config const seed: uint(32) = 314159;
 config const correctness = false;
 
-extern proc c_sin(size: uint(32), iterations: int(32), resArray: c_ptr(real(32))): real(32);
-extern proc c_table(size: uint(32), iterations: int(32), resArray: c_ptr(real(32))): real(32);
+extern proc c_sin(size: uint(32),
+                  iterations: int(32),
+                  seed: uint(32),
+                  resArray: c_ptr(real(32))): real(32);
+extern proc c_table(size: uint(32),
+                    iterations: int(32),
+                    seed: uint(32),
+                    resArray: c_ptr(real(32))): real(32);
 
 proc sin_calc(size: uint(32), iterations : int(32)): real(32) {
 
@@ -114,7 +120,7 @@ proc main()
     var resArray = allocate(real(32), iterations);
 
     c_calc.start();
-    var c_calc_res = c_sin(size, iterations, resArray);
+    var c_calc_res = c_sin(size, iterations, seed, resArray);
     c_calc.stop();
     write("C Calculated: ");
     if correctness
@@ -122,7 +128,7 @@ proc main()
       else writeln(c_calc.elapsed(), " seconds");
 
     c_lookup.start();
-    var table_calc_res = c_table(size, iterations, resArray);
+    var table_calc_res = c_table(size, iterations, seed, resArray);
     c_lookup.stop();
     write("C Lookup: ");
     if correctness
diff --git a/test/studies/sinLUT/chplSinReplicated.good b/test/studies/sinLUT/chplSinReplicated.good
index ae73c1548c6a..b3da301ebcb9 100644
--- a/test/studies/sinLUT/chplSinReplicated.good
+++ b/test/studies/sinLUT/chplSinReplicated.good
@@ -1,4 +1,2 @@
-Chapel Calculated: -1.2311
-Chapel Lookup: -1.2311
-C Calculated: -1.2311
-C Lookup: -1.2311
+Chapel Calculated == Chapel Lookup
+C Calculated == C Lookup
diff --git a/test/studies/sinLUT/chplSinReplicatedReplicand.chpl b/test/studies/sinLUT/chplSinReplicatedReplicand.chpl
index 5c23af01a7a8..313f7e7dd17f 100644
--- a/test/studies/sinLUT/chplSinReplicatedReplicand.chpl
+++ b/test/studies/sinLUT/chplSinReplicatedReplicand.chpl
@@ -5,11 +5,17 @@ use Math;
 use CTypes;
 use ReplicatedDist;
 
-config const seed = 314159;
+config const seed: uint(32) = 314159;
 config const correctness = false;
 
-extern proc c_sin(size: uint(32), iterations: int(32), resArray: c_ptr(real(32))): real(32);
-extern proc c_table(size: uint(32), iterations: int(32), resArray: c_ptr(real(32))): real(32);
+extern proc c_sin(size: uint(32),
+                  iterations: int(32),
+                  seed: uint(32),
+                  resArray: c_ptr(real(32))): real(32);
+extern proc c_table(size: uint(32),
+                    iterations: int(32),
+                    seed: uint(32),
+                    resArray: c_ptr(real(32))): real(32);
 
 proc sin_calc(size: uint(32), iterations : int(32)): real(32) {
 
@@ -114,7 +120,7 @@ proc main()
     var resArray = allocate(real(32), iterations);
 
     c_calc.start();
-    var c_calc_res = c_sin(size, iterations, resArray);
+    var c_calc_res = c_sin(size, iterations, seed, resArray);
     c_calc.stop();
     write("C Calculated: ");
     if correctness
@@ -122,7 +128,7 @@ proc main()
       else writeln(c_calc.elapsed(), " seconds");
 
     c_lookup.start();
-    var table_calc_res = c_table(size, iterations, resArray);
+    var table_calc_res = c_table(size, iterations, seed, resArray);
     c_lookup.stop();
     write("C Lookup: ");
     if correctness
diff --git a/test/studies/sinLUT/chplSinReplicatedReplicand.good b/test/studies/sinLUT/chplSinReplicatedReplicand.good
index ae73c1548c6a..b3da301ebcb9 100644
--- a/test/studies/sinLUT/chplSinReplicatedReplicand.good
+++ b/test/studies/sinLUT/chplSinReplicatedReplicand.good
@@ -1,4 +1,2 @@
-Chapel Calculated: -1.2311
-Chapel Lookup: -1.2311
-C Calculated: -1.2311
-C Lookup: -1.2311
+Chapel Calculated == Chapel Lookup
+C Calculated == C Lookup