Merge branch 'timedalta_rounding' of https://github.com/faucon/matplotlib into faucon-timedalta_rounding

efiring · efiring · commit 13a11b4e4c3a · 2011-08-20T11:33:06.000-10:00
diff --git a/lib/matplotlib/dates.py b/lib/matplotlib/dates.py
@@ -299,9 +299,15 @@ def drange(dstart, dend, delta):
             delta.microseconds/MUSECONDS_PER_DAY)
     f1 = _to_ordinalf(dstart)
     f2 = _to_ordinalf(dend)
-    return np.arange(f1, f2, step)
-
-
+    
+    num = int(np.ceil((f2-f1)/step))        #calculate the difference between dend and dstart in times of delta
+    dinterval_end = dstart + num*delta      #calculate end of the interval which will be generated
+    if dinterval_end >= dend:               #ensure, that an half open interval will be generated [dstart, dend)
+        dinterval_end -= delta              #if the endpoint is greated than dend, just subtract one delta
+        num -= 1
+        
+    f2 = _to_ordinalf(dinterval_end) #new float-endpoint
+    return np.linspace(f1, f2, num+1)
 
 ### date tickers and formatters ###
 
diff --git a/lib/matplotlib/tests/test_dates.py b/lib/matplotlib/tests/test_dates.py
@@ -2,7 +2,7 @@
 import numpy as np
 from matplotlib.testing.decorators import image_comparison, knownfailureif, cleanup
 import matplotlib.pyplot as plt
-from nose.tools import assert_raises
+from nose.tools import assert_raises, assert_equal
 import warnings
 
 @image_comparison(baseline_images=['date_empty'])
@@ -69,7 +69,9 @@ def test_too_many_date_ticks():
     # setting equal datetimes triggers and expander call in
     # transforms.nonsingular which results in too many ticks in the
     # DayLocator.  This should trigger a Locator.MAXTICKS RuntimeError
-    warnings.filterwarnings('ignore','Attempting to set identical left==right results\\nin singular transformations; automatically expanding.\\nleft=\d*\.\d*, right=\d*\.\d*',UserWarning,module='matplotlib.axes')
+    warnings.filterwarnings('ignore',
+        'Attempting to set identical left==right results\\nin singular transformations; automatically expanding.\\nleft=\d*\.\d*, right=\d*\.\d*',
+        UserWarning, module='matplotlib.axes')
     t0 = datetime.datetime(2000, 1, 20)
     tf = datetime.datetime(2000, 1, 20)
     fig = plt.figure()
@@ -134,6 +136,31 @@ def test_DateFormatter():
     ax.autoscale_view()
     fig.autofmt_xdate()
 
+def test_drange():
+    '''This test should check if drange works as expected, and if all the rounding errors
+    are fixed'''
+    from matplotlib import dates
+    start = datetime.datetime(2011, 1,1, tzinfo=dates.UTC)
+    end = datetime.datetime(2011, 1, 2, tzinfo=dates.UTC)
+    delta = datetime.timedelta(hours=1)
+    #We expect 24 values in drange(start, end, delta), because drange returns dates from
+    #an half open interval [start, end)
+    assert_equal(24, len(dates.drange(start, end, delta)))
+
+    #if end is a little bit later, we expect the range to contain one element more
+    end = end +datetime.timedelta(microseconds=1)
+    assert_equal(25, len(dates.drange(start, end, delta)))
+
+    #reset end
+    end = datetime.datetime(2011, 1, 2, tzinfo=dates.UTC)
+
+    #and tst drange with "complicated" floats:
+    # 4 hours = 1/6 day, this is an "dangerous" float
+    delta = datetime.timedelta(hours=4)
+    daterange = dates.drange(start, end, delta)
+    assert_equal(6, len(daterange))
+    assert_equal(dates.num2date(daterange[-1]), end-delta)
+
 #@image_comparison(baseline_images=['empty_date_bug'])
 @cleanup
 @knownfailureif(True)
