[gegl] perf: fix convergence test; lower no. of iterations

[Ell <ell src gnome org>]

commit cd5e2a1a8ad75f0ca0ee094f79887ce098aee09f
Author: Ell <ell_se yahoo com>
Date:   Mon Dec 17 04:10:37 2018 -0500

    perf: fix convergence test; lower no. of iterations
    
    In test-common.h, fix the convergence test, which should allow us
    to lower the number of iterations without sacrificing too much
    accuracy.

 perf/test-common.h | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)
---
diff --git a/perf/test-common.h b/perf/test-common.h
index 12cf97c77..e07e425db 100644
--- a/perf/test-common.h
+++ b/perf/test-common.h
@@ -8,8 +8,8 @@
                            more noise, increase this number towards 1.0,
                            like 0.8 */
 #define BAIL_THRESHOLD 0.001
-#define BAIL_COUNT     75
-#define MIN_ITER       100
+#define BAIL_COUNT     20
+#define MIN_ITER       20
 
 static long ticks_start;
 
@@ -40,20 +40,19 @@ int  converged = 0;
 long ticks_iter_start = 0;
 long iter_db[ITERATIONS];
 int iter_no = 0;
+float prev_median = 0.0;
 
 void test_start (void)
 {
   ticks_start = babl_ticks ();
   iter_no = 0;
   converged = 0;
+  prev_median = 0.0;
 }
 
-float prev_median = 0.0;
-
 static void test_start_iter (void)
 {
   ticks_iter_start = babl_ticks ();
-  prev_median = -1.0;
 }
 
 
@@ -78,7 +77,8 @@ static void test_end_iter (void)
   iter_no++;
 
   median = compute_median ();
-  if (iter_no > MIN_ITER && fabs(1.0-fabs(median - prev_median * 1.0)/median) < BAIL_THRESHOLD) /// median < 
0.05)
+  if (iter_no > MIN_ITER &&
+      fabs ((median - prev_median) / median) < BAIL_THRESHOLD)
    {
      /* we've converged */
      converged++;