TST: Create tests for accelerated SIRT and MLEM reconstruction algori…

…thms (#487)

Previously, there have not been any methods to test that CUDA enabled TomoPy has been built properly. This introduces one unit test for each of the two CUDA eligible reconstruction algorithms, SIRT and MLEM.

Co-authored-by: Daniel Ching <carterbox@users.noreply.github.com>

test/test_tomopy/test_recon/test_algorithm.py

@@ -112,15 +112,18 @@ def test_gridrec(self):
             recon(self.prj, self.ang, algorithm='gridrec', filter_name='parzen'),
             read_file('gridrec_parzen.npy'), rtol=1e-2)
         assert_allclose(
-            recon(self.prj, self.ang, algorithm='gridrec', filter_name='butterworth'),
+            recon(self.prj, self.ang, algorithm='gridrec',
+                  filter_name='butterworth'),
             read_file('gridrec_butterworth.npy'), rtol=1e-2)
 
     def test_mlem(self):
-        # FIXME: Make separate tests for each back-end
-        os.environ["TOMOPY_USE_C_MLEM"] = "1"
-        assert_allclose(
-            recon(self.prj, self.ang, algorithm='mlem', num_iter=4),
-            read_file('mlem.npy'), rtol=1e-2)
+        result = recon(self.prj, self.ang, algorithm='mlem', num_iter=4)
+        assert_allclose(result, read_file('mlem.npy'), rtol=1e-2)
+
+    def test_mlem_accel(self):
+        result = recon(self.prj, self.ang, algorithm='mlem', num_iter=4,
+                       accelerated=True)
+        assert_allclose(result, read_file('mlem_accel.npy'), rtol=1e-2)
 
     def test_osem(self):
         assert_allclose(
@@ -148,11 +151,13 @@ def test_pml_quad(self):
             read_file('pml_quad.npy'), rtol=1e-2)
 
     def test_sirt(self):
-        # FIXME: Make separate tests for each back-end
-        os.environ["TOMOPY_USE_C_SIRT"] = "1"
-        r_sirt = recon(self.prj, self.ang, algorithm='sirt', num_iter=4)
-        c_sirt = read_file('sirt.npy')
-        assert_allclose(r_sirt, c_sirt, rtol=1e-2)
+        result = recon(self.prj, self.ang, algorithm='sirt', num_iter=4)
+        assert_allclose(result, read_file('sirt.npy'), rtol=1e-2)
+
+    def test_sirt_accel(self):
+        result = recon(self.prj, self.ang, algorithm='sirt',
+                       num_iter=4, accelerated=True)
+        assert_allclose(result, read_file('sirt_accel.npy'), rtol=1e-2)
 
     def test_tv(self):
         assert_allclose(
@@ -167,4 +172,4 @@ def test_grad(self):
     def test_tikh(self):
         assert_allclose(
             recon(self.prj, self.ang, algorithm='tikh', num_iter=4),
-            read_file('tikh.npy'), rtol=1e-2)
+            read_file('tikh.npy'), rtol=1e-2)