Omptimize performance in Waveform.astype()

madarrays/waveform.py

@@ -736,7 +736,7 @@ class Waveform(MadArray):
             if (np.issubdtype(dtype, np.floating) or
                     np.issubdtype(dtype, np.complexfloating)):
                 y.clip(min_value=-1, max_value=(1 - np.finfo(dtype).eps))
-                y = np.array(y).astype(dtype)
+                y = np.asarray(y, dtype=dtype)
 
             elif np.issubdtype(dtype, np.integer):
                 target_type_info = np.iinfo(dtype)
@@ -745,7 +745,7 @@ class Waveform(MadArray):
                              target_type_info.min)
                 y.clip(min_value=np.iinfo(dtype).min,
                        max_value=np.iinfo(dtype).max)
-                y = np.array(y).astype(dtype)
+                y = np.asarray(y, dtype=dtype)
 
             else:
                 errmsg = 'Unsupported target type {}.'
@@ -760,16 +760,16 @@ class Waveform(MadArray):
                 y = ((super(type(y), y).astype(dtype) - zero)
                      / (int_range // 2))
                 y.clip(min_value=-1, max_value=1-np.finfo(dtype).eps)
-                y = np.array(y).astype(dtype)
+                y = np.asarray(y, dtype=dtype)
 
             elif np.issubdtype(dtype, np.integer):
                 y = y.astype(dtype=np.float64)
                 y = y.astype(dtype=dtype)
-                y = np.array(y)
+                y = np.asarray(y)
 
             elif np.issubdtype(dtype, np.complexfloating):
                 y = y.astype(dtype=np.float64)
-                y = np.array(y).astype(dtype=dtype)
+                y = np.asarray(y, dtype=dtype)
 
             else:
                 errmsg = 'Unsupported target type {}.'