diff --git a/opencl_fdtd/kernels/common.cl b/opencl_fdtd/kernels/common.cl
index 8c58d48..769c248 100644
--- a/opencl_fdtd/kernels/common.cl
+++ b/opencl_fdtd/kernels/common.cl
@@ -2,7 +2,7 @@
 /* Common code for E, H updates
  *
  * Template parameters:
- *  ftype	type name (e.g. float or double)
+ *  ftype       type name (e.g. float or double)
  *  shape       list of 3 ints specifying shape of fields
  */
 #}
diff --git a/opencl_fdtd/kernels/update_j.cl b/opencl_fdtd/kernels/update_j.cl
index 4d7f64d..2682f39 100644
--- a/opencl_fdtd/kernels/update_j.cl
+++ b/opencl_fdtd/kernels/update_j.cl
@@ -1,11 +1,11 @@
 /*
- *  Update E-field from J field 
+ *  Update E-field from J field
  *
  *  Template parameters:
  *   common_header: Rendered contents of common.cl
  *
  *  OpenCL args:
- *   E, Jr, Ji, c, s, xmin, xmax, ymin, ymax, zmin, zmax   
+ *   E, Jr, Ji, c, s, xmin, xmax, ymin, ymax, zmin, zmax
  */
 
 {{common_header}}
diff --git a/opencl_fdtd/simulation.py b/opencl_fdtd/simulation.py
index 9dd90c0..03b5588 100644
--- a/opencl_fdtd/simulation.py
+++ b/opencl_fdtd/simulation.py
@@ -286,13 +286,13 @@ class Simulation(object):
             alpha_max = pml['cfs_alpha']
 
             def par(x):
-                scaling = ((x / (pml['thickness'])) ** pml['m'])
+                scaling = (x / pml['thickness']) ** pml['m']
                 sigma = scaling * sigma_max
                 kappa = 1 + scaling * (kappa_max - 1)
                 alpha = ((1 - x / pml['thickness']) ** pml['ma']) * alpha_max
                 p0 = numpy.exp(-(sigma / kappa + alpha) * self.dt)
                 p1 = sigma / (sigma + kappa * alpha) * (p0 - 1)
-                p2 = 1/kappa
+                p2 = 1 / kappa
                 return p0, p1, p2
 
             xe, xh = (numpy.arange(1, pml['thickness'] + 1, dtype=self.arg_type)[::-1] for _ in range(2))