hotfix - check for nan in dataprep windowsize

f could get value NaN. Added is not np.isinf()

rowers/dataprep.py

@@ -1,23 +1,26 @@
 # All the data preparation, data cleaning and data mangling should
 # be defined here
-from rowers.models import Workout, User, Rower, StrokeData
+from rowers.models import Workout, StrokeData,Team
+
+import pytz
+
 from rowingdata import rowingdata as rrdata
 
-from rowers.tasks import handle_sendemail_unrecognized
-from rowers.tasks import handle_zip_file
-import pytz
 from rowingdata import rower as rrower
-from rowingdata import main as rmain
 
 from rowingdata import get_file_type, get_empower_rigging
 
+from rowers.tasks import handle_sendemail_unrecognized
+from rowers.tasks import handle_zip_file
+
 from pandas import DataFrame, Series
-from pytz import timezone as tz, utc
+
 from django.utils import timezone
-from time import strftime, strptime, mktime, time, daylight
-import arrow
 from django.utils.timezone import get_current_timezone
 
+from time import strftime
+import arrow
+
 thetimezone = get_current_timezone()
 from rowingdata import (
     TCXParser, RowProParser, ErgDataParser,
@@ -30,7 +33,6 @@ from rowingdata import (
     summarydata, get_file_type,
 )
 
-from rowers.models import Team
 from rowers.metrics import axes
 from async_messages import messages as a_messages
 import os
@@ -52,7 +54,6 @@ import sys
 import utils
 import datautils
 from utils import lbstoN
-from scipy.interpolate import griddata
 
 from timezonefinder import TimezoneFinder
 
@@ -1704,7 +1705,7 @@ def dataprep(rowdatadf, id=0, bands=True, barchart=True, otwpower=True,
         rhythm = 0.0 * forceratio
 
     f = rowdatadf['TimeStamp (sec)'].diff().mean()
-    if f != 0:
+    if f != 0 and not np.isinf(f):
         windowsize = 2 * (int(10. / (f))) + 1
     else:
         windowsize = 1