Revision: 7707
http://matplotlib.svn.sourceforge.net/matplotlib/?rev=7707&view=rev
Author: jswhit
Date: 2009-09-08 12:06:35 +0000 (Tue, 08 Sep 2009)
Log Message:
-----------
update to latest version from netcdf4-python
Modified Paths:
--------------
trunk/toolkits/basemap/lib/mpl_toolkits/basemap/netcdftime.py
Modified: trunk/toolkits/basemap/lib/mpl_toolkits/basemap/netcdftime.py
===================================================================
--- trunk/toolkits/basemap/lib/mpl_toolkits/basemap/netcdftime.py
2009-09-08 01:53:12 UTC (rev 7706)
+++ trunk/toolkits/basemap/lib/mpl_toolkits/basemap/netcdftime.py
2009-09-08 12:06:35 UTC (rev 7707)
@@ -934,18 +934,38 @@
cdftime = utime(units,calendar=calendar)
return cdftime.num2date(times)
-
def _check_index(indices, dates, nctime, calendar):
- """Assert that the time indices given correspond to the given dates."""
- t = numpy.empty(len(indices), nctime.dtype)
- for n,i in enumerate(indices):
- t[n] = nctime[i]
- assert numpy.all( num2date(t, nctime.units, calendar) == dates)
+ """Return True if the time indices given correspond to the given dates,
+ False otherwise.
+
+ Parameters:
+ indices : sequence of integers
+ Positive integers indexing the time variable.
-def date2index(dates, nctime, calendar=None):
+ dates : sequence of datetime objects
+ Reference dates.
+
+ nctime : netCDF Variable object
+ NetCDF time object.
+
+ calendar : string
+ Calendar of nctime.
+ """
+ if (indices <0).any():
+ return False
+
+ if (indices >= nctime.shape[0]).any():
+ return False
+
+ t = nctime[indices]
+ return numpy.all( num2date(t, nctime.units, calendar) == dates)
+
+
+
+def date2index(dates, nctime, calendar=None, select='exact'):
"""
- date2index(dates, nctime, calendar=None)
+ date2index(dates, nctime, calendar=None, select='exact')
Return indices of a netCDF time variable corresponding to the given dates.
@@ -953,7 +973,8 @@
The datetime objects should not include a time-zone offset.
@param nctime: A netCDF time variable object. The nctime object must have a
- C{units} attribute.
+ C{units} attribute. The entries are assumed to be stored in increasing
+ order.
@param calendar: Describes the calendar used in the time calculation.
Valid calendars C{'standard', 'gregorian', 'proleptic_gregorian'
@@ -961,32 +982,54 @@
Default is C{'standard'}, which is a mixed Julian/Gregorian calendar
If C{calendar} is None, its value is given by C{nctime.calendar} or
C{standard} if no such attribute exists.
+
+ @param select: C{'exact', 'before', 'after', 'nearest'}
+ The index selection method. C{exact} will return the indices perfectly
+ matching the dates given. C{before} and C{after} will return the indices
+ corresponding to the dates just before or just after the given dates if
+ an exact match cannot be found. C{nearest} will return the indices that
+ correpond to the closest dates.
"""
# Setting the calendar.
if calendar is None:
calendar = getattr(nctime, 'calendar', 'standard')
num = numpy.atleast_1d(date2num(dates, nctime.units, calendar))
-
- index = numpy.empty(numpy.alen(dates), int)
-
+
# Trying to infer the correct index from the starting time and the stride.
- try:
- t0, t1 = nctime[:2]
- dt = t1 - t0
- index[:] = (num-t0)/dt
+ # This assumes that the times are increasing uniformly.
+ t0, t1 = nctime[:2]
+ dt = t1 - t0
+ index = numpy.array((num-t0)/dt, int)
- # Checking that the index really corresponds to the given date.
- _check_index(index, dates, nctime, calendar)
-
- except AssertionError:
-
- # If check fails, use brute force method.
- index[:] = numpy.digitize(num, nctime[:]) - 1
-
- # Perform check again.
- _check_index(index, dates, nctime, calendar)
-
+ # Checking that the index really corresponds to the given date.
+ # If the times do not correspond, then it means that the times
+ # are not increasing uniformly and we try the bisection method.
+ if not _check_index(index, dates, nctime, calendar):
+
+ # Use the bisection method. Assumes the dates are ordered.
+ import bisect
+
+ index = numpy.array([bisect.bisect_left(nctime, n) for n in num], int)
+
+ nomatch = num2date(nctime[index], nctime.units) != dates
+
+ if select == 'exact':
+ if not (num2date(nctime[index], nctime.units) == dates).all():
+ raise ValueError, 'Dates not found.'
+
+ elif select == 'before':
+ index[nomatch] -= 1
+
+ elif select == 'after':
+ pass
+
+ elif select == 'nearest':
+ index[nomatch] = index[nomatch] - 1 * ( num[nomatch] <
(nctime[index[nomatch]-1] + nctime[index[nomatch]]) / 2. )
+
+ else:
+ raise ValueError, select
+
# convert numpy scalars or single element arrays to python ints.
index = _toscalar(index)
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