[ncl-talk] Bug in cd_string
Jared Lee
jaredlee at ucar.edu
Tue Oct 14 10:33:13 MDT 2014
I just checked my test script again, replacing cd_string with ut_string,
and ut_string gives me the correct output. So the bug is something wrong
in cd_string but not in ut_string. Thanks for the suggestion, Mary. I'll
just go ahead and use ut_string until a bug fix is released for cd_string.
Jared
On Mon, Oct 13, 2014 at 11:07 PM, Kyle Griffin <ksgriffin2 at wisc.edu> wrote:
> I remember some discussion on this topic on the list a couple years ago.
> Although I didn't find that particular thread, a similar one came to light
> from 2008 highlighting the problem at hand.
>
> https://www.ncl.ucar.edu/Support/talk_archives/2008/0946.html
>
> If I remember from the last time, the fact that most time values must be
> doubles costs some precision when it comes to seconds (I didn't think
> minutes were affected, although it appears they are indirectly) and the
> dates are also not accurate in very early years, although for a different
> reason (prior to the last major shift in the Gregorian calendar, I believe,
> late 1600s?).
>
> With increasingly high-resolution datasets (e.g. the "new" HRRR from NCEP
> - data every 15 minutes, http://www.nco.ncep.noaa.gov/pmb/products/hrrr/),
> both spatially and temporally, the minutes portion of this bug might be
> worth tackling as the potential issues now might be more frequent than they
> may have been in the past.
>
>
> Kyle
>
> ----------------------------------------
> Kyle S. Griffin
> Department of Atmospheric and Oceanic Sciences
> University of Wisconsin - Madison
> Room 1421
> 1225 W Dayton St, Madison, WI 53706
> Email: ksgriffin2 at wisc.edu
>
> On Mon, Oct 13, 2014 at 11:48 PM, Mary Haley <haley at ucar.edu> wrote:
>
>> Jared,
>>
>> I will try to look into this, but I don't know how soon I can get to it.
>> Does ut_string give you the same problem?
>>
>> I think we may already have a ticket on this issue, NCL-1829, so I will
>> add your nice test script to this ticket.
>>
>>
>> --Mary
>>
>> On Fri, Oct 10, 2014 at 9:43 AM, Jared Lee <jaredlee at ucar.edu> wrote:
>>
>>> Hi, I believe I've found a bug in the cd_string function in NCL v6.2.0
>>> (I'm running on NCAR's Yellowstone supercomputer). It seems like it's
>>> possibly a rounding error. Here's sample code to demonstrate the bug:
>>>
>>> =====
>>> load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/contributed.ncl"
>>> load "$NCARG_ROOT/lib/ncarg/nclscripts/contrib/cd_string.ncl"
>>>
>>> begin
>>> do testMin = 0, 60, 1
>>> testMin at units = "minutes since 2014-01-01 00:00:00"
>>> print("testMin = "+testMin+" -> "+cd_string(testMin, "%N/%D/%Y,
>>> %H:%M:%S"))
>>> end do
>>> do testSec = 0, 3600, 60
>>> testSec at units = "seconds since 1970-01-01 00:00:00"
>>> print("testSec = "+testSec+" -> "+cd_string(testSec, "%N/%D/%Y,
>>> %H:%M:%S"))
>>> end do
>>> end
>>> =====
>>>
>>> This script gives the following output. Notice that the seconds field
>>> sometimes returns a value of "00", and sometimes returns a value of "60".
>>> This means that sometimes the minutes value is not correct, which is
>>> problematic for my applications, where I'm trying to match a string
>>> returned from cd_string with an observation time in a data file (and those,
>>> of course, never have 60 in the seconds field). Note also that this is a
>>> problem that occurs with different time units. Here is the output:
>>>
>>> =====
>>> (0) testMin = 0 -> 01/01/2014, 00:00:00
>>> (0) testMin = 1 -> 01/01/2014, 00:00:60
>>> (0) testMin = 2 -> 01/01/2014, 00:01:60
>>> (0) testMin = 3 -> 01/01/2014, 00:02:60
>>> (0) testMin = 4 -> 01/01/2014, 00:03:60
>>> (0) testMin = 5 -> 01/01/2014, 00:04:60
>>> (0) testMin = 6 -> 01/01/2014, 00:05:60
>>> (0) testMin = 7 -> 01/01/2014, 00:06:60
>>> (0) testMin = 8 -> 01/01/2014, 00:08:00
>>> (0) testMin = 9 -> 01/01/2014, 00:09:00
>>> (0) testMin = 10 -> 01/01/2014, 00:10:00
>>> (0) testMin = 11 -> 01/01/2014, 00:11:00
>>> (0) testMin = 12 -> 01/01/2014, 00:12:00
>>> (0) testMin = 13 -> 01/01/2014, 00:13:00
>>> (0) testMin = 14 -> 01/01/2014, 00:14:00
>>> (0) testMin = 15 -> 01/01/2014, 00:15:00
>>> (0) testMin = 16 -> 01/01/2014, 00:15:60
>>> (0) testMin = 17 -> 01/01/2014, 00:16:60
>>> (0) testMin = 18 -> 01/01/2014, 00:17:60
>>> (0) testMin = 19 -> 01/01/2014, 00:18:60
>>> (0) testMin = 20 -> 01/01/2014, 00:19:60
>>> (0) testMin = 21 -> 01/01/2014, 00:20:60
>>> (0) testMin = 22 -> 01/01/2014, 00:21:60
>>> (0) testMin = 23 -> 01/01/2014, 00:23:00
>>> (0) testMin = 24 -> 01/01/2014, 00:24:00
>>> (0) testMin = 25 -> 01/01/2014, 00:25:00
>>> (0) testMin = 26 -> 01/01/2014, 00:26:00
>>> (0) testMin = 27 -> 01/01/2014, 00:27:00
>>> (0) testMin = 28 -> 01/01/2014, 00:28:00
>>> (0) testMin = 29 -> 01/01/2014, 00:29:00
>>> (0) testMin = 30 -> 01/01/2014, 00:30:00
>>> (0) testMin = 31 -> 01/01/2014, 00:30:60
>>> (0) testMin = 32 -> 01/01/2014, 00:31:60
>>> (0) testMin = 33 -> 01/01/2014, 00:32:60
>>> (0) testMin = 34 -> 01/01/2014, 00:33:60
>>> (0) testMin = 35 -> 01/01/2014, 00:34:60
>>> (0) testMin = 36 -> 01/01/2014, 00:35:60
>>> (0) testMin = 37 -> 01/01/2014, 00:36:60
>>> (0) testMin = 38 -> 01/01/2014, 00:38:00
>>> (0) testMin = 39 -> 01/01/2014, 00:39:00
>>> (0) testMin = 40 -> 01/01/2014, 00:40:00
>>> (0) testMin = 41 -> 01/01/2014, 00:41:00
>>> (0) testMin = 42 -> 01/01/2014, 00:42:00
>>> (0) testMin = 43 -> 01/01/2014, 00:43:00
>>> (0) testMin = 44 -> 01/01/2014, 00:44:00
>>> (0) testMin = 45 -> 01/01/2014, 00:45:00
>>> (0) testMin = 46 -> 01/01/2014, 00:45:60
>>> (0) testMin = 47 -> 01/01/2014, 00:46:60
>>> (0) testMin = 48 -> 01/01/2014, 00:47:60
>>> (0) testMin = 49 -> 01/01/2014, 00:48:60
>>> (0) testMin = 50 -> 01/01/2014, 00:49:60
>>> (0) testMin = 51 -> 01/01/2014, 00:50:60
>>> (0) testMin = 52 -> 01/01/2014, 00:51:60
>>> (0) testMin = 53 -> 01/01/2014, 00:53:00
>>> (0) testMin = 54 -> 01/01/2014, 00:54:00
>>> (0) testMin = 55 -> 01/01/2014, 00:55:00
>>> (0) testMin = 56 -> 01/01/2014, 00:56:00
>>> (0) testMin = 57 -> 01/01/2014, 00:57:00
>>> (0) testMin = 58 -> 01/01/2014, 00:58:00
>>> (0) testMin = 59 -> 01/01/2014, 00:59:00
>>> (0) testMin = 60 -> 01/01/2014, 01:00:00
>>> (0) testSec = 0 -> 01/01/1970, 00:00:00
>>> (0) testSec = 60 -> 01/01/1970, 00:00:60
>>> (0) testSec = 120 -> 01/01/1970, 00:02:00
>>> (0) testSec = 180 -> 01/01/1970, 00:03:00
>>> (0) testSec = 240 -> 01/01/1970, 00:03:60
>>> (0) testSec = 300 -> 01/01/1970, 00:04:60
>>> (0) testSec = 360 -> 01/01/1970, 00:06:00
>>> (0) testSec = 420 -> 01/01/1970, 00:07:00
>>> (0) testSec = 480 -> 01/01/1970, 00:07:60
>>> (0) testSec = 540 -> 01/01/1970, 00:08:60
>>> (0) testSec = 600 -> 01/01/1970, 00:10:00
>>> (0) testSec = 660 -> 01/01/1970, 00:11:00
>>> (0) testSec = 720 -> 01/01/1970, 00:11:60
>>> (0) testSec = 780 -> 01/01/1970, 00:12:60
>>> (0) testSec = 840 -> 01/01/1970, 00:14:00
>>> (0) testSec = 900 -> 01/01/1970, 00:15:00
>>> (0) testSec = 960 -> 01/01/1970, 00:15:60
>>> (0) testSec = 1020 -> 01/01/1970, 00:17:00
>>> (0) testSec = 1080 -> 01/01/1970, 00:18:00
>>> (0) testSec = 1140 -> 01/01/1970, 00:18:60
>>> (0) testSec = 1200 -> 01/01/1970, 00:19:60
>>> (0) testSec = 1260 -> 01/01/1970, 00:21:00
>>> (0) testSec = 1320 -> 01/01/1970, 00:22:00
>>> (0) testSec = 1380 -> 01/01/1970, 00:22:60
>>> (0) testSec = 1440 -> 01/01/1970, 00:23:60
>>> (0) testSec = 1500 -> 01/01/1970, 00:25:00
>>> (0) testSec = 1560 -> 01/01/1970, 00:26:00
>>> (0) testSec = 1620 -> 01/01/1970, 00:26:60
>>> (0) testSec = 1680 -> 01/01/1970, 00:27:60
>>> (0) testSec = 1740 -> 01/01/1970, 00:29:00
>>> (0) testSec = 1800 -> 01/01/1970, 00:30:00
>>> (0) testSec = 1860 -> 01/01/1970, 00:30:60
>>> (0) testSec = 1920 -> 01/01/1970, 00:32:00
>>> (0) testSec = 1980 -> 01/01/1970, 00:33:00
>>> (0) testSec = 2040 -> 01/01/1970, 00:33:60
>>> (0) testSec = 2100 -> 01/01/1970, 00:34:60
>>> (0) testSec = 2160 -> 01/01/1970, 00:36:00
>>> (0) testSec = 2220 -> 01/01/1970, 00:37:00
>>> (0) testSec = 2280 -> 01/01/1970, 00:37:60
>>> (0) testSec = 2340 -> 01/01/1970, 00:38:60
>>> (0) testSec = 2400 -> 01/01/1970, 00:40:00
>>> (0) testSec = 2460 -> 01/01/1970, 00:41:00
>>> (0) testSec = 2520 -> 01/01/1970, 00:41:60
>>> (0) testSec = 2580 -> 01/01/1970, 00:42:60
>>> (0) testSec = 2640 -> 01/01/1970, 00:44:00
>>> (0) testSec = 2700 -> 01/01/1970, 00:45:00
>>> (0) testSec = 2760 -> 01/01/1970, 00:45:60
>>> (0) testSec = 2820 -> 01/01/1970, 00:47:00
>>> (0) testSec = 2880 -> 01/01/1970, 00:48:00
>>> (0) testSec = 2940 -> 01/01/1970, 00:48:60
>>> (0) testSec = 3000 -> 01/01/1970, 00:49:60
>>> (0) testSec = 3060 -> 01/01/1970, 00:51:00
>>> (0) testSec = 3120 -> 01/01/1970, 00:52:00
>>> (0) testSec = 3180 -> 01/01/1970, 00:52:60
>>> (0) testSec = 3240 -> 01/01/1970, 00:53:60
>>> (0) testSec = 3300 -> 01/01/1970, 00:55:00
>>> (0) testSec = 3360 -> 01/01/1970, 00:56:00
>>> (0) testSec = 3420 -> 01/01/1970, 00:56:60
>>> (0) testSec = 3480 -> 01/01/1970, 00:57:60
>>> (0) testSec = 3540 -> 01/01/1970, 00:59:00
>>> (0) testSec = 3600 -> 01/01/1970, 01:00:00
>>> =====
>>>
>>> Is there an easy fix to this bug?
>>>
>>> Jared
>>>
>>> --
>>> ===============================
>>> Jared A. Lee, Ph.D.
>>> Project Scientist I
>>> Research Applications Laboratory
>>> National Center for Atmospheric Research
>>> Boulder, Colorado, USA
>>>
>>> Email: jaredlee at ucar.edu (w)
>>> Phone: 303.497.8485 (w)
>>> Web: https://staff.ucar.edu/users/jaredlee
>>> ===============================
>>>
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>>>
>>
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>
--
===============================
Jared A. Lee, Ph.D.
Project Scientist I
Research Applications Laboratory
National Center for Atmospheric Research
Boulder, Colorado, USA
Email: jaredlee at ucar.edu (w)
Phone: 303.497.8485 (w)
Web: https://staff.ucar.edu/users/jaredlee
===============================
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