From 1af3d69cde636c1f76cb9eb895ad6da6e1f085ce Mon Sep 17 00:00:00 2001
From: Steven Silvester <steven.silvester@ieee.org>
Date: Fri, 28 Dec 2012 01:33:01 -0600
Subject: [PATCH] BUG: Fixed another division error

---
 skimage/exposure/_adapthist.py          |  8 ++++----
 skimage/exposure/tests/test_exposure.py | 14 ++++++++------
 2 files changed, 12 insertions(+), 10 deletions(-)

diff --git a/skimage/exposure/_adapthist.py b/skimage/exposure/_adapthist.py
index 91787513..c2b85d8d 100644
--- a/skimage/exposure/_adapthist.py
+++ b/skimage/exposure/_adapthist.py
@@ -158,11 +158,11 @@ def _clahe(image, ntiles_x, ntiles_y, clip_limit, nbins=128):
     for y in range(ntiles_y + 1):
         xstart = 0
         if y == 0:  # special case: top row
-            ystep = y_size / 2
+            ystep = int(y_size / 2)
             yU = 0
             yB = 0
         elif y == ntiles_y:  # special case: bottom row
-            ystep = y_size / 2
+            ystep = int(y_size / 2)
             yU = ntiles_y - 1
             yB = yU
         else:  # default values
@@ -172,11 +172,11 @@ def _clahe(image, ntiles_x, ntiles_y, clip_limit, nbins=128):
 
         for x in range(ntiles_x + 1):
             if x == 0:  # special case: left column
-                xstep = x_size / 2
+                xstep = int(x_size / 2)
                 xL = 0
                 xR = 0
             elif x == ntiles_x:  # special case: right column
-                xstep = x_size / 2
+                xstep = int(x_size / 2)
                 xL = ntiles_x - 1
                 xR = xL
             else:  # default values
diff --git a/skimage/exposure/tests/test_exposure.py b/skimage/exposure/tests/test_exposure.py
index a5d72cbb..6c7dd9a4 100644
--- a/skimage/exposure/tests/test_exposure.py
+++ b/skimage/exposure/tests/test_exposure.py
@@ -87,8 +87,9 @@ def test_adapthist_scalar():
     full_scale = skimage.exposure.rescale_intensity(skimage.img_as_uint(img))
 
     assert_almost_equal = np.testing.assert_almost_equal
-    assert peak_snr(full_scale, adapted) > 95.0
-    assert norm_brightness_err(full_scale, adapted) < 0.05
+    assert_almost_equal(peak_snr(full_scale, adapted), 101.231, 3)
+    assert_almost_equal(norm_brightness_err(full_scale, adapted),
+                        0.041, 3)
     return img, adapted
 
 
@@ -102,8 +103,8 @@ def test_adapthist_grayscale():
                         nbins=128)
     assert_almost_equal = np.testing.assert_almost_equal
     assert img.shape == adapted.shape
-    assert peak_snr(img, adapted) > 95.0
-    assert norm_brightness_err(img, adapted) < 0.05
+    assert_almost_equal(peak_snr(img, adapted), 97.949, 3)
+    assert_almost_equal(norm_brightness_err(img, adapted), 0.03077, 3)
     return data, adapted
 
 
@@ -117,8 +118,9 @@ def test_adapthist_color():
     assert adapted.max() == 1.0
     assert img.shape == adapted.shape
     full_scale = skimage.exposure.rescale_intensity(img)
-    assert peak_snr(img, adapted) > 95.0
-    assert norm_brightness_err(img, adapted) < 0.05
+    assert_almost_equal(peak_snr(full_scale, adapted), 102.940, 3)
+    assert_almost_equal(norm_brightness_err(full_scale, adapted),
+                        0.0110, 3)
     return data, adapted