Don't cast extreme values to ints in analyze_surface_position_data().

Without the cast, we can also use this function to fit floating point
data, where the deflection and offset ranges are less than one
(e.g. nanometer sized sweeps stored in meters).

diff --git a/pypiezo/surface.py b/pypiezo/surface.py
index 7d7f8b554089c37fc3b26d118e5391e6a45a3c05..f038de437938b517294afa1b85499f2858bd6507 100644 (file)
--- a/pypiezo/surface.py
+++ b/pypiezo/surface.py
@@ -174,17 +174,17 @@ def analyze_surface_position_data(
     #   = p0 + p1 p2 + p3 (x-p2)   for x >= p2
     dump_before_index = 0 # 25 # HACK!!
     # Generate a reasonable guess...
-    start_pos = int(data['z'].min())
-    final_pos = int(data['z'].max())
+    start_pos = data['z'].min()
+    final_pos = data['z'].max()
     if final_pos == start_pos:
         raise SurfaceError()
-    start_def = int(data['deflection'].min())
-    final_def = int(data['deflection'].max())
+    start_def = data['deflection'].min()
+    final_def = data['deflection'].max()
     # start_def and start_pos are probably for 2 different points
-    _LOG.info('min deflection %d, max deflection %d'
-               % (start_def, final_def))
-    _LOG.info('min position %d, max position %d'
-               % (start_pos, final_pos))
+    _LOG.info('min deflection {}, max deflection {}'.format(
+            start_def, final_def))
+    _LOG.info('min position {}, max position {}'.format(
+            start_pos, final_pos))
 
     left_offset   = start_def
     left_slope    = 0