[ncl-talk] A bug of use cd_calendar , second = 60

Tue Feb 21 16:33:46 MST 2017

Xiaobin,

As Dave said, we should have a potential fix for this in the next release,
but I wanted to test this first.

I can't quite seem to reproduce the same results as you.  Could you write
the time array to a netCDF file and send to to me? You should be able to
just temporarily add these two lines of code:

fout = addfile("marytime.nc","c")
fout->time = time

and then send me the "marytime.nc" file.

Thanks!

--Mary

On Sun, Feb 19, 2017 at 3:14 PM, Dave Allured - NOAA Affiliate <
dave.allured at noaa.gov> wrote:

> Xiaobin,
>
> There is a known bug in the cd_calendar function in NCL version 6.3.0.
> For time values that are extremely close to 0 or 60 seconds, the function
> sometimes outputs 60 seconds, and fails to increment the number of
> minutes.  Notice in your original message, some of the output values for
> minutes were incorrect, as well as values for seconds.  This bug should
> be fixed in the next NCL release.
>
> In the meantime, you may be able to avoid the bug by adding a small
> fraction of one minute to your time values.  This should work because it
> seems like your intended values are even minutes with zero seconds:
>
>   time(:) = time(:) + (0.01 / 3600)     ; add 0.01 seconds to "hours
> since..."
>   print (sprintf ("%24.11f", time))
>
> (0)     3615141.00000277767
> (1)     3615141.08333611069
> (2)     3615141.16666944465
> (3)     3615141.25000277767
> (4)     3615141.33333611069
> (5)     3615141.41666944465
> (6)     3615141.50000277767
> (7)     3615141.58333611069
> (8)     3615141.66666944465
> (9)     3615141.75000277767
> (10)    3615141.83333611069
> (11)    3615141.91666944465
> (12)    3615142.00000277767
> (13)    3615142.08333611069
> (14)    3615142.16666944465
> (15)    3615142.25000277767
>
> Now your code to compute hours, minutes, seconds, etc. with cd_calendar
> seems to work okay.  When you use "tointeger", the extra 0.01 seconds is
> removed safely:
>
> second = tointeger (utc_date(:,5))
> etc.
>
>   print (date_str)
>
> (0) 2013_05_31_21_00_00
> (1) 2013_05_31_21_05_00
> (2) 2013_05_31_21_10_00
> (3) 2013_05_31_21_15_00
> (4) 2013_05_31_21_20_00
> (5) 2013_05_31_21_25_00
> (6) 2013_05_31_21_30_00
> (7) 2013_05_31_21_35_00
> (8) 2013_05_31_21_40_00
> (9) 2013_05_31_21_45_00
> (10) 2013_05_31_21_50_00
> (11) 2013_05_31_21_55_00
> (12) 2013_05_31_22_00_00
> (13) 2013_05_31_22_05_00
> (14) 2013_05_31_22_10_00
> (15) 2013_05_31_22_15_00
>
> Please check all output values to make sure this fix works for all cases
> in your data.
>
> --Dave
>
>
> On Sun, Feb 19, 2017 at 1:55 AM, qiuxiaobin.tj <qiuxiaobin.tj at qq.com>
> wrote:
>
>> *Dear all*
>>
>> *I met a bug when use cd_calendar. Some times it return second = 60.*
>> *Here is the input time:*
>> Variable: time
>> Type: double
>> Total Size: 680 bytes
>>             85 values
>> Number of Dimensions: 1
>> Dimensions and sizes: [time | 85]
>> Coordinates:
>> Number Of Attributes: 3
>>   _FillValue : 9.969209968386869e+36
>>   calendar : gregorian
>>   units : hours since 1601-01-01 00:00:0.0
>> (0) 3615141
>> (1) 3615141.083333333
>> (2) 3615141.166666667
>> (3) 3615141.25
>> (4) 3615141.333333333
>> (5) 3615141.416666667
>> (6) 3615141.5
>> (7) 3615141.583333333
>> (8) 3615141.666666667
>> (9) 3615141.75
>> (10) 3615141.833333333
>> (11) 3615141.916666667
>> (12) 3615142
>> (13) 3615142.083333333
>> (14) 3615142.166666667
>> (15) 3615142.25
>> ..............
>>
>> *Here is the scripts:*
>>
>> utc_date = cd_calendar(time, 0)
>> ;
>> ; Store return information into more meaningful variables.
>> ;
>> year   = tointeger(utc_date(:,0))    ; Convert to integer for
>> month  = tointeger(utc_date(:,1))    ; use sprinti
>> day    = tointeger(utc_date(:,2))
>> hour   = tointeger(utc_date(:,3))
>> minute = tointeger(utc_date(:,4))
>> second = tointeger(utc_date(:,5))
>>
>> ; Write out strings in the format "hhZ dd mmm yyyy".
>>
>> date_str = sprinti("%0.4i",year) + "_" + sprinti("%0.2i",month) + "_" +
>> sprinti("%0.2i",day) + "_" + sprinti("%0.2i",hour) + "_" +
>> sprinti("%0.2i",minute) + "_" + sprinti("%0.2i",second)
>>
>> print(date_str)
>>
>> *Here is the output:*
>> Variable: date_str
>> Type: string
>> Total Size: 680 bytes
>>             85 values
>> Number of Dimensions: 1
>> Dimensions and sizes: [85]
>> Coordinates:
>> (0) 2013_05_31_21_00_00
>> (1) 2013_05_31_21_05_00
>> (2) 2013_05_31_21_*09_60*
>> (3) 2013_05_31_21_15_00
>> (4) 2013_05_31_21_20_00
>> (5) 2013_05_31_21_*24_60*
>> (6) 2013_05_31_21_30_00
>> (7) 2013_05_31_21_35_00
>> (8) 2013_05_31_21_*39_60*
>> (9) 2013_05_31_21_45_00
>> (10) 2013_05_31_21_50_00
>> (11) 2013_05_31_21_*54_60*
>> (12) 2013_05_31_22_00_00
>> (13) 2013_05_31_22_05_00
>> (14) 2013_05_31_22_*09_60*
>> (15) 2013_05_31_22_15_00
>>
>> *How to overcome this? Thanks a lot.*
>>
>> *Best,*
>> *Xiaobin*
>>
>
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