Thank you Dave,
I have tested *modified **copy_VarAtts procedure according to you
suggestion. It is working fine.*
*
*
*Thank you very much*
Variable: x
Type: float
Total Size: 12 bytes
3 values
Number of Dimensions: 1
Dimensions and sizes: [3]
Coordinates:
Number Of Attributes: 2
long_name : test_variable
_FillValue : -999
*Variable: l*
*Type: logical*
*Total Size: 12 bytes*
* 3 values*
*Number of Dimensions: 1*
*Dimensions and sizes:** **[3]*
*Coordinates: *
*Number Of Attributes: 1*
* _FillValue :** **Missing*
*
*
*
*
*(0)** **procedure: copy_VarAtts(x,l) *
*
*
*
*
*Variable: l*
*Type: logical*
*Total Size: 12 bytes*
* 3 values*
*Number of Dimensions: 1*
*Dimensions and sizes:** **[3]*
*Coordinates: *
*Number Of Attributes: 2*
* long_name :** **test_variable*
* _FillValue :** **Missing*
________________________________________________________
But I am getting different result in the case of normal assignment.
I am using NCAR Command Language Version 5.1.1 in fedora 11
________________________________________________________
Variable: x
Type: float
Total Size: 12 bytes
3 values
Number of Dimensions: 1
Dimensions and sizes: [3]
Coordinates:
Number Of Attributes: 2
long_name : test_variable
_FillValue : -999
Variable: l
Type: logical
Total Size: 12 bytes
3 values
Number of Dimensions: 1
Dimensions and sizes: [3]
Coordinates:
Number Of Attributes: 1
_FillValue : Missing
*(0)** **normal assignment : l = x *
*
*
*
*
*Variable: l*
*Type: logical*
*Total Size: 12 bytes*
* 3 values*
*Number of Dimensions: 1*
*Dimensions and sizes:** **[3]*
*Coordinates: *
*Number Of Attributes: 2*
* long_name :** **test_variable*
* _FillValue :** **True*
On 3 March 2011 01:37, David Brown <dbrown@ucar.edu> wrote:
>
> copy_VarAtts is an NCL source code procedure. It does not not have special
> handling for the _FillValue attribute. Since the _FillValue type must agree
> with type of the variable is belongs to, the float variable's _FillValue
> attribute value is coerced to the logical type the same as any other value
> would be. The rule for converting any numeric type to logical is that 0
> converts to False and all other values convert to True. Note that during
> normal assignment of a float variable to a logical variable this copying
> with coercion of the _FillValue is prevented by NCL internally.
>
> For example:
>
> x = new(3,float)
> l = new(3,logical)
> printVarSummary(x)
> l = x
> printVarSummary(l)
>
> gives:
>
> Variable: x
> Type: float
> Total Size: 12 bytes
> 3 values
> Number of Dimensions: 1
> Dimensions and sizes: [3]
> Coordinates:
> Number Of Attributes: 1
> _FillValue : 9.96921e+36
> ncl 3> l = x
> ncl 4> printVarSummary(l)
>
> Variable: l
> Type: logical
> Total Size: 12 bytes
> 3 values
> Number of Dimensions: 1
> Dimensions and sizes: [3]
> Coordinates:
> Number Of Attributes: 1
> _FillValue : Missing
>
> But copy_VarAtts is a very simple procedure, and because it directly
> assigns the attribute values itself, NCL does not, nor should it, prevent
> the assignment. You could easily create your own version of copy_VarAtts
> that would catch this problem and handle it. We will discuss whether we
> should do the same.
>
> Here is the complete code of copy_VarAtts:
>
> undef("copy_VarAtts")
> procedure copy_VarAtts(var_from,var_to)
> local att_names, i
> begin
> att_names =getvaratts(var_from);
> if(.not.all(ismissing(att_names)))
> do i = 0,dimsizes(att_names)-1
> if (isatt(var_to,att_names(i))) then
> delete(var_to@$att_names(i)$) ; var_from att may be diff
> size/type
> end if
> var_to@$att_names(i)$ = var_from@$att_names(i)$
> end do
> end if
> end
>
> Perhaps (untested) add the following after do i = 0,dimsizes(att_names)-1:
>
> if (islogical(var_to) .and. attnames(i) .eq. "_FillValue") then
> ; don't delete or assign to a logical _FillValue attribute
> continue
> end if
>
> -dave
>
>
>
>
> On Mar 2, 2011, at 5:38 AM, gibies george wrote:
>
> Here is some part of my NCL script, where I am using a user defined
> resource variable "predef" (a logical variable with some attributes attached
> to it) which is to be given as argument to a function to carry some
> information about the data to be read from a source file.
>
> I have used copy_VarAtts function to get these attributes from a data
> variable named "fcstdata"
>
> *During this operation the fill value of the logical variable is happens
> to be "True"* .
>
> Why is it so ?
> __________________________________________
> print(predef)
> __________________________________________
> Variable: predef
> Type: logical
> Total Size: 4 bytes
> 1 values
> Number of Dimensions: 1
> Dimensions and sizes: [1]
> Coordinates:
> Number Of Attributes: 15
> datavar : precip
> nosclr : 1
> novctr : 0
> ssnend : 9
> ssnbegin : 6
> season : jjas
> loneast : 360
> lonwest : 0
> latnorth : 30
> latsouth : -30
> region : tropics
> anal_end_year : 2001
> anal_start_year : 1980
> anal : skill
> _FillValue : Missing
> (0) True
>
> __________________________________________
> delete(predef)
> predef = new (1,logical)
> print(predef)
> __________________________________________
> Variable: predef
> Type: logical
> Total Size: 4 bytes
> 1 values
> Number of Dimensions: 1
> Dimensions and sizes: [1]
> Coordinates:
> Number Of Attributes: 1
> _FillValue : Missing
> (0) Missing
>
> __________________________________________
> printVarSummary(fcstdata)
> __________________________________________
> Variable: fcstdata
> Type: float
> Total Size: 304128 bytes
> 76032 values
> Number of Dimensions: 4
> Dimensions and sizes: [time | 22] x [season | 1] x [lat | 24] x [lon |
> 144]
> Coordinates:
> time: [1980..2001]
> season: [jjas..jjas]
> lat: [-28.75..28.75]
> lon: [1.25..358.75]
> Number Of Attributes: 7
> units : mm/day
> region : tropics
> ssnend : 9
> ssnbegin : 6
> long_name : jjas Means: Average Monthly Rate of Precipitation
> season : jjas
> _FillValue : -9.96921e+36
>
> __________________________________________
> copy_VarAtts(fcstdata,predef)
> print(predef)
> __________________________________________
> Variable: predef
> Type: logical
> Total Size: 4 bytes
> 1 values
> Number of Dimensions: 1
> Dimensions and sizes: [1]
> Coordinates:
> Number Of Attributes: 7
> * _FillValue :** **True*
> * season :** **jjas*
> * long_name :** **jjas Means: Average Monthly Rate of Precipitation*
> * ssnbegin :** **6*
> * ssnend :** **9*
> * region :** **tropics*
> * units :** **mm/day*
> *(0)** **True*
>
> __________________________________________
> predef = True print(predef)
> __________________________________________
> Variable: predef
> Type: logical
> Total Size: 4 bytes
> 1 values
> Number of Dimensions: 1
> Dimensions and sizes: [1]
> Coordinates:
> Number Of Attributes: 7
> _FillValue : True
> season : jjas
> long_name : jjas Means: Average Monthly Rate of Precipitation
> ssnbegin : 6
> ssnend : 9
> region : tropics
> units : mm/day
> (0) True
>
>
> On 2 March 2011 16:08, gibies george <gibies@tropmet.res.in> wrote:
>
>>
>>
>> On 2 March 2011 11:01, gibies george <gibies@tropmet.res.in> wrote:
>>
>>> Thank you Dave.
>>>
>>> Thanking you very much for all your supports.
>>>
>>> I am also thankful to Mary and Dennis for
>>> the suggestions and support, with great patience through out the long
>>> discussion (Both online and offline)
>>> .
>>>
>>>
>>> On 2 March 2011 06:40, David Brown <dbrown@ucar.edu> wrote:
>>>
>>>> Hi Gibies,
>>>>
>>>> There is a problem here and thank you for pointing it out. However, it
>>>> is not what it might seem at first glance. There is one issue, admittedly
>>>> somewhat serious: the conversion of the default logical missing value to a
>>>> string is not working correctly. When you call 'print' with your variable
>>>> 'full' set to the default missing value, "Missing", as follows:
>>>>
>>>> print("full = " + full)
>>>>
>>>> the value of 'full' gets converted to a string -- incorrectly, it turns
>>>> out. However, the variable 'full' still has the correct value and the .not.
>>>> operator is working correctly. You can see this if you print the variable
>>>> and the expression without converting them to a string. If the first part of
>>>> your code is changed from:
>>>>
>>>> print("A1 : Defineing full = new(1,logical)")
>>>> full = new(1,logical)
>>>>
>>>> print("full = "+full)
>>>> print(".not.full = "+.not.full)
>>>>
>>>> to
>>>>
>>>> print("A1 : Defining full = new(1,logical)")
>>>> full = new(1,logical)
>>>>
>>>> print(full)
>>>> print(.not.full)
>>>>
>>>> Instead of your output below you get:
>>>>
>>>> (0) A1 : Defining full = new(1,logical)
>>>>
>>>>
>>>> Variable: full
>>>> Type: logical
>>>> Total Size: 4 bytes
>>>> 1 values
>>>> Number of Dimensions: 1
>>>> Dimensions and sizes: [1]
>>>> Coordinates:
>>>> Number Of Attributes: 1
>>>> _FillValue : Missing
>>>> (0) Missing
>>>> (0) Missing
>>>>
>>>> which is correct based on *the rule that any operation applied to a
>>>> missing value yields a missing value*.
>>>>
>>>
>> Actually I considered fill-value of the logical variable as a default
>> state of a switch.
>>
>> I have used the not operator in that sense.
>>
>> I was not aware that you you were considering it as missing value same as
>> in the case of all the other data-type.
>>
>>
>>>> Setting the missing value to True, as you do in case B, inevitably leads
>>>> to results that seem weird, even though all the results in your B scenario
>>>> are correct by the rule above. Likewise with scenario C where the missing
>>>> value is set to False. In most cases, although allowed, it is not advisable
>>>> to change the missing value of logical variables from the default.
>>>>
>>>
>> Isn't it possible to have such a different philosophy in the case of
>> logical datatype.
>>
>> I mean an exception for logical variable alone from "*the rule that any
>> operation applied to a missing value yields a missing value*", only for
>> the case when fill-value is set explicitly to a value other than missing.
>>
>>
>>> Case D is the same as A and has the same error. Thanks much for pointing
>>>> this out. I'm not sure how this has managed to slip by for such a long time.
>>>> But it will have a high priority for getting fixed quickly.
>>>> -dave
>>>>
>>>>
>>>> On Mar 1, 2011, at 9:34 AM, gibies george wrote:
>>>>
>>>> Here I have analysed 12 different cases of logical variable find
>>>> its behavior to not operator.
>>>>
>>>> My script is attached
>>>>
>>>> The output is as follows.
>>>>
>>>> Please note the potions with red font colour.
>>>>
>>>> I am using NCAR Command Language Version 5.1.1 on Fedora 11 operating
>>>> system
>>>>
>>>> (0) A1 : Defineing full = new(1,logical)
>>>> *(0)** **full = True*
>>>> *(0)** **.not.full = True*
>>>> (0) case A2 : full = True
>>>> (0) full = True
>>>> (0) .not.full = False
>>>> (0) case A3 : full = False
>>>> (0) full = False
>>>> (0) .not.full = True
>>>> (0) B1 : Defineing full = new(1,logical,True)
>>>> *(0)** **full = True*
>>>> *(0)** **.not.full = True*
>>>> (0) case B2 : full = True
>>>> *(0)** **full = True*
>>>> *(0)** **.not.full = True*
>>>> (0) case B3 : full = False
>>>> (0) full = False
>>>> (0) .not.full = True
>>>> (0) C1 : Defineing full = new(1,logical,False)
>>>> *(0)** **full = False*
>>>> *(0)** **.not.full = False*
>>>> (0) case C2 : full = True
>>>> (0) full = True
>>>> (0) .not.full = False
>>>> (0) case C3 : full = False
>>>> *(0)** **full = False*
>>>> *(0)** **.not.full = False*
>>>> (0) D1 : Defineing full = new(1,logical)
>>>> *(0)** **full = True*
>>>> *(0)** **.not.full = True*
>>>> (0) case D2 : full = True
>>>> (0) full = True
>>>> (0) .not.full = False
>>>> (0) case D3 : full = False
>>>> (0) full = False
>>>> (0) .not.full = True
>>>>
>>>>
>>>> --
>>>> *Gibies George, CSIR-RF,
>>>> Climate and Global Modelling Division,
>>>> Indian Institute of Tropical Meteorology,
>>>> Dr. Homi Bhabha Road,
>>>> NCL (P. O.), Pashan,
>>>> Pune 411008, India.*
>>>>
>>>> *http://sites.google.com/site/gibiesge/*
>>>>
>>>> Please Think about the environment. Save paper; Save Trees; and don't
>>>> print this e-mail unless it is necessary.
>>>> <trial1.ncl>_______________________________________________
>>>> ncl-talk mailing list
>>>> List instructions, subscriber options, unsubscribe:
>>>> http://mailman.ucar.edu/mailman/listinfo/ncl-talk
>>>>
>>>>
>>>>
>>>
>>>
>>> --
>>> *Gibies George, CSIR-RF,
>>> Climate and Global Modelling Division,
>>> Indian Institute of Tropical Meteorology,
>>> Dr. Homi Bhabha Road,
>>> NCL (P. O.), Pashan,
>>> Pune 411008, India.*
>>>
>>> *http://sites.google.com/site/gibiesge/*
>>>
>>> Please Think about the environment. Save paper; Save Trees; and don't
>>> print this e-mail unless it is necessary.
>>>
>>
>>
>>
>> --
>> *Gibies George, CSIR-RF,
>> Climate and Global Modelling Division,
>> Indian Institute of Tropical Meteorology,
>> Dr. Homi Bhabha Road,
>> NCL (P. O.), Pashan,
>> Pune 411008, India.*
>>
>> *http://sites.google.com/site/gibiesge/*
>>
>> Please Think about the environment. Save paper; Save Trees; and don't
>> print this e-mail unless it is necessary.
>>
>
>
>
> --
> *Gibies George, CSIR-RF,
> Climate and Global Modelling Division,
> Indian Institute of Tropical Meteorology,
> Dr. Homi Bhabha Road,
> NCL (P. O.), Pashan,
> Pune 411008, India.*
>
> *http://sites.google.com/site/gibiesge/*
>
> Please Think about the environment. Save paper; Save Trees; and don't print
> this e-mail unless it is necessary.
> _______________________________________________
> ncl-talk mailing list
> List instructions, subscriber options, unsubscribe:
> http://mailman.ucar.edu/mailman/listinfo/ncl-talk
>
>
>
-- *Gibies George, CSIR-RF, Climate and Global Modelling Division, Indian Institute of Tropical Meteorology, Dr. Homi Bhabha Road, NCL (P. O.), Pashan, Pune 411008, India.* *http://sites.google.com/site/gibiesge/* Please Think about the environment. Save paper; Save Trees; and don't print this e-mail unless it is necessary.
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