| more bugs in envi !!! [message #35725] |
Fri, 11 July 2003 05:41  |
gauravjn123
Messages: 7
Registered: July 2003
|
Junior Member |
|
|
Hi folks!
Sorry to trouble u again....but envi seems to be just going above my
head...there is another problem that i am facing:
Please go through the 2 functions:
1.function example,b1
help,b1
end
2.function example,b1,b2
help,b1
end
Now could anyone tell me why these 2 codes are producing different
final answers??? I just cant find any reason for it.
One more problem :
'b1' is a positive array and 'avgb1' is a positive number but when i
use the formula : result=b1*100/avgb1
print, result
, the answer that i get is a negative array.
Whereas if i use the formula : result=b1/avgb1
print, result * 100
, then i get a positive array
I hope to hear the answers to these questions soon. Thnxx
Byee
Gaurav
|
|
|
|
| Re: more bugs in envi !!! [message #35796 is a reply to message #35725] |
Tue, 15 July 2003 17:17  |
marc schellens[1]
Messages: 183
Registered: January 2000
|
Senior Member |
|
|
Could you post the COMPLETE stuff?
I mean the calling procedure or function?
Try to delete everything which is irrelevant.
I hardly assume, that the mistake lies somewhere there.
Maybe another subroutine changes some of its arguments?
Regards,
marc
Gaurav wrote:
> Hi!
> Okay...i shall give u the outputs also. Here are the functions:
>
> 1.;Stored in file trash.pro
> function ex,b1
> print,' This is the function ex,b1'
> print,size(b1)
> help,b1
> end
> 2.;Stored in file trash2.pro
> function ex2,b1,b2
> print,'This is the function ex2,b1,b2'
> print,size(b1)
> help,b1
> end
> The outputs of these functions are :
>
> ENVI>
> % Compiled module: TRASH.
>
> ENVI>
> % Compiled module: TRASH2.
>
> ENVI>
> This is the function ex,b1
> 2 5 5 4
> 25
> B1 FLOAT = Array[5, 5]
> This is the function ex,b1
> 2 5 5 4
> 25
> B1 FLOAT = Array[5, 5]
> This is the function ex,b1
> 2 5 5 2
> 25
> B1 INT = Array[5, 5]
> This is the function ex,b1
> 2 568 653 2
> 370904
> B1 INT = Array[568, 653]
>
> ENVI>
> This is the function ex2,b1,b2
> 2 5 5 4
> 25
> B1 FLOAT = Array[5, 5]
> This is the function ex2,b1,b2
> 2 5 5 4
> 25
> B1 FLOAT = Array[5, 5]
> This is the function ex2,b1,b2
> 2 5 5 2
> 25
> B1 INT = Array[5, 5]
> This is the function ex2,b1,b2
> 2 568 326 2
> 185168
> B1 INT = Array[568, 326]
> This is the function ex2,b1,b2
> 2 568 327 2
> 185736
> B1 INT = Array[568, 327]
>
> ENVI>
>
> Hope this helps you in finding out the answer to my question.
>
> Gaurav Jain
>
>
>
> Marc Schellens <m_schellens@hotmail.com> wrote in message news:<3F12DAB7.607@hotmail.com>...
>
>> Would be helpful if you post WHAT they output also.
>> And then of course the context from which you call them...
>> (Two functions with the same name cannot live in one (IDL-) program)
>>
>> Gaurav wrote:
>>
>>> Hi all!
>>> Thanx for the help...well u both were right...i was under the wrong
>>> impression that i had defined it as a long integer...but i hadn't. But
>>> i still cant find out why these 2 functions are producing different
>>> outputs :
>>> Please go through the 2 functions:
>>>
>>>
>>>> >1.function example,b1
>>>> > help,b1
>>>> > end
>>>> >2.function example,b1,b2
>>>> > help,b1
>>>> > end
>>>> >
>>>> > Now could anyone tell me why these 2 codes are producing different
>>>> >final answers??? I just cant find any reason for it.
>>>>
>>>
>>> Gaurav Jain
>>> ENST-Bretagne
>>>
>>>
>>> Marc Schellens <m_schellens@hotmail.com> wrote in message news:<3F115ED4.6040200@hotmail.com>...
>>>
>>>
>>>> >Hi folks!
>>>> > Sorry to trouble u again....but envi seems to be just going above my
>>>> >head...there is another problem that i am facing:
>>>> >Please go through the 2 functions:
>>>> >
>>>> >1.function example,b1
>>>> > help,b1
>>>> > end
>>>> >2.function example,b1,b2
>>>> > help,b1
>>>> > end
>>>> >
>>>> > Now could anyone tell me why these 2 codes are producing different
>>>> >final answers??? I just cant find any reason for it.
>>>> >
>>>> >One more problem :
>>>> >
>>>> >'b1' is a positive array and 'avgb1' is a positive number but when i
>>>> >use the formula : result=b1*100/avgb1
>>>> > print, result
>>>> >, the answer that i get is a negative array.
>>>> >
>>>> > Whereas if i use the formula : result=b1/avgb1
>>>> > print, result * 100
>>>> >, then i get a positive array
>>>> >
>>>>
>>>> Even without knowing ENVI, the second problem isn't a bug in ENVI.
>>>>
>>>> A integer occupies (in IDL) 16-bit, and therfore covers a range form
>>>> -32768 to
>>>> 32767
>>>>
>>>> anything larger (or smaller) cannot be represented and therefore you
>>>> observe an 'overflow', resulting in a negative number.
>>>> IDL evalutates your expressinon from left to right, the
>>>> overflow occurs after the multiplication with 100.
>>>> In the second case the division is done first and thus the value seems
>>>> to be small enough not to overflow in the later multiplication.
>>>>
>>>> The solution is to convert your b1 array to LONG.
>>>> But did you notice that you do an integer division?
>>>> 1/2 equals 0.
>>>> Maybe you want to use FLOAT or DOUBLE.
>>>>
>>>> hdh,
>>>> marc
>>>
|
|
|
|
| Re: more bugs in envi !!! [message #35798 is a reply to message #35725] |
Wed, 16 July 2003 00:33 |
gauravjn123
Messages: 7
Registered: July 2003
|
Junior Member |
|
|
Hi!
Okay...i shall give u the outputs also. Here are the functions:
1.;Stored in file trash.pro
function ex,b1
print,' This is the function ex,b1'
print,size(b1)
help,b1
end
2.;Stored in file trash2.pro
function ex2,b1,b2
print,'This is the function ex2,b1,b2'
print,size(b1)
help,b1
end
The outputs of these functions are :
ENVI>
% Compiled module: TRASH.
ENVI>
% Compiled module: TRASH2.
ENVI>
This is the function ex,b1
2 5 5 4
25
B1 FLOAT = Array[5, 5]
This is the function ex,b1
2 5 5 4
25
B1 FLOAT = Array[5, 5]
This is the function ex,b1
2 5 5 2
25
B1 INT = Array[5, 5]
This is the function ex,b1
2 568 653 2
370904
B1 INT = Array[568, 653]
ENVI>
This is the function ex2,b1,b2
2 5 5 4
25
B1 FLOAT = Array[5, 5]
This is the function ex2,b1,b2
2 5 5 4
25
B1 FLOAT = Array[5, 5]
This is the function ex2,b1,b2
2 5 5 2
25
B1 INT = Array[5, 5]
This is the function ex2,b1,b2
2 568 326 2
185168
B1 INT = Array[568, 326]
This is the function ex2,b1,b2
2 568 327 2
185736
B1 INT = Array[568, 327]
ENVI>
Hope this helps you in finding out the answer to my question.
Gaurav Jain
Marc Schellens <m_schellens@hotmail.com> wrote in message news:<3F12DAB7.607@hotmail.com>...
> Would be helpful if you post WHAT they output also.
> And then of course the context from which you call them...
> (Two functions with the same name cannot live in one (IDL-) program)
>
> Gaurav wrote:
>> Hi all!
>> Thanx for the help...well u both were right...i was under the wrong
>> impression that i had defined it as a long integer...but i hadn't. But
>> i still cant find out why these 2 functions are producing different
>> outputs :
>> Please go through the 2 functions:
>>
>>>> 1.function example,b1
>>>> help,b1
>>>> end
>>>> 2.function example,b1,b2
>>>> help,b1
>>>> end
>>>>
>>>> Now could anyone tell me why these 2 codes are producing different
>>>> final answers??? I just cant find any reason for it.
>>>
>>
>> Gaurav Jain
>> ENST-Bretagne
>>
>>
>> Marc Schellens <m_schellens@hotmail.com> wrote in message news:<3F115ED4.6040200@hotmail.com>...
>>
>>>> Hi folks!
>>>> Sorry to trouble u again....but envi seems to be just going above my
>>>> head...there is another problem that i am facing:
>>>> Please go through the 2 functions:
>>>>
>>>> 1.function example,b1
>>>> help,b1
>>>> end
>>>> 2.function example,b1,b2
>>>> help,b1
>>>> end
>>>>
>>>> Now could anyone tell me why these 2 codes are producing different
>>>> final answers??? I just cant find any reason for it.
>>>>
>>>> One more problem :
>>>>
>>>> 'b1' is a positive array and 'avgb1' is a positive number but when i
>>>> use the formula : result=b1*100/avgb1
>>>> print, result
>>>> , the answer that i get is a negative array.
>>>>
>>>> Whereas if i use the formula : result=b1/avgb1
>>>> print, result * 100
>>>> , then i get a positive array
>>>>
>>>
>>> Even without knowing ENVI, the second problem isn't a bug in ENVI.
>>>
>>> A integer occupies (in IDL) 16-bit, and therfore covers a range form
>>> -32768 to
>>> 32767
>>>
>>> anything larger (or smaller) cannot be represented and therefore you
>>> observe an 'overflow', resulting in a negative number.
>>> IDL evalutates your expressinon from left to right, the
>>> overflow occurs after the multiplication with 100.
>>> In the second case the division is done first and thus the value seems
>>> to be small enough not to overflow in the later multiplication.
>>>
>>> The solution is to convert your b1 array to LONG.
>>> But did you notice that you do an integer division?
>>> 1/2 equals 0.
>>> Maybe you want to use FLOAT or DOUBLE.
>>>
>>> hdh,
>>> marc
>>
|
|
|
|
| Re: more bugs in envi !!! [message #35808 is a reply to message #35725] |
Mon, 14 July 2003 09:30 |
marc schellens[1]
Messages: 183
Registered: January 2000
|
Senior Member |
|
|
Would be helpful if you post WHAT they output also.
And then of course the context from which you call them...
(Two functions with the same name cannot live in one (IDL-) program)
Gaurav wrote:
> Hi all!
> Thanx for the help...well u both were right...i was under the wrong
> impression that i had defined it as a long integer...but i hadn't. But
> i still cant find out why these 2 functions are producing different
> outputs :
> Please go through the 2 functions:
>
>>> 1.function example,b1
>>> help,b1
>>> end
>>> 2.function example,b1,b2
>>> help,b1
>>> end
>>>
>>> Now could anyone tell me why these 2 codes are producing different
>>> final answers??? I just cant find any reason for it.
>>
>
> Gaurav Jain
> ENST-Bretagne
>
>
> Marc Schellens <m_schellens@hotmail.com> wrote in message news:<3F115ED4.6040200@hotmail.com>...
>
>>> Hi folks!
>>> Sorry to trouble u again....but envi seems to be just going above my
>>> head...there is another problem that i am facing:
>>> Please go through the 2 functions:
>>>
>>> 1.function example,b1
>>> help,b1
>>> end
>>> 2.function example,b1,b2
>>> help,b1
>>> end
>>>
>>> Now could anyone tell me why these 2 codes are producing different
>>> final answers??? I just cant find any reason for it.
>>>
>>> One more problem :
>>>
>>> 'b1' is a positive array and 'avgb1' is a positive number but when i
>>> use the formula : result=b1*100/avgb1
>>> print, result
>>> , the answer that i get is a negative array.
>>>
>>> Whereas if i use the formula : result=b1/avgb1
>>> print, result * 100
>>> , then i get a positive array
>>>
>>
>> Even without knowing ENVI, the second problem isn't a bug in ENVI.
>>
>> A integer occupies (in IDL) 16-bit, and therfore covers a range form
>> -32768 to
>> 32767
>>
>> anything larger (or smaller) cannot be represented and therefore you
>> observe an 'overflow', resulting in a negative number.
>> IDL evalutates your expressinon from left to right, the
>> overflow occurs after the multiplication with 100.
>> In the second case the division is done first and thus the value seems
>> to be small enough not to overflow in the later multiplication.
>>
>> The solution is to convert your b1 array to LONG.
>> But did you notice that you do an integer division?
>> 1/2 equals 0.
>> Maybe you want to use FLOAT or DOUBLE.
>>
>> hdh,
>> marc
>
|
|
|
|
| Re: more bugs in envi !!! [message #35811 is a reply to message #35725] |
Mon, 14 July 2003 13:07 |
gauravjn123
Messages: 7
Registered: July 2003
|
Junior Member |
|
|
Hi all!
Thanx for the help...well u both were right...i was under the wrong
impression that i had defined it as a long integer...but i hadn't. But
i still cant find out why these 2 functions are producing different
outputs :
Please go through the 2 functions:
>>
>> 1.function example,b1
>> help,b1
>> end
>> 2.function example,b1,b2
>> help,b1
>> end
>>
>> Now could anyone tell me why these 2 codes are producing different
>> final answers??? I just cant find any reason for it.
Gaurav Jain
ENST-Bretagne
Marc Schellens <m_schellens@hotmail.com> wrote in message news:<3F115ED4.6040200@hotmail.com>...
>> Hi folks!
>> Sorry to trouble u again....but envi seems to be just going above my
>> head...there is another problem that i am facing:
>> Please go through the 2 functions:
>>
>> 1.function example,b1
>> help,b1
>> end
>> 2.function example,b1,b2
>> help,b1
>> end
>>
>> Now could anyone tell me why these 2 codes are producing different
>> final answers??? I just cant find any reason for it.
>>
>> One more problem :
>>
>> 'b1' is a positive array and 'avgb1' is a positive number but when i
>> use the formula : result=b1*100/avgb1
>> print, result
>> , the answer that i get is a negative array.
>>
>> Whereas if i use the formula : result=b1/avgb1
>> print, result * 100
>> , then i get a positive array
>>
>
> Even without knowing ENVI, the second problem isn't a bug in ENVI.
>
> A integer occupies (in IDL) 16-bit, and therfore covers a range form
> -32768 to
> 32767
>
> anything larger (or smaller) cannot be represented and therefore you
> observe an 'overflow', resulting in a negative number.
> IDL evalutates your expressinon from left to right, the
> overflow occurs after the multiplication with 100.
> In the second case the division is done first and thus the value seems
> to be small enough not to overflow in the later multiplication.
>
> The solution is to convert your b1 array to LONG.
> But did you notice that you do an integer division?
> 1/2 equals 0.
> Maybe you want to use FLOAT or DOUBLE.
>
> hdh,
> marc
|
|
|
|
| Re: more bugs in envi !!! [message #35817 is a reply to message #35725] |
Sun, 13 July 2003 06:29 |
marc schellens[1]
Messages: 183
Registered: January 2000
|
Senior Member |
|
|
> Hi folks!
> Sorry to trouble u again....but envi seems to be just going above my
> head...there is another problem that i am facing:
> Please go through the 2 functions:
>
> 1.function example,b1
> help,b1
> end
> 2.function example,b1,b2
> help,b1
> end
>
> Now could anyone tell me why these 2 codes are producing different
> final answers??? I just cant find any reason for it.
>
> One more problem :
>
> 'b1' is a positive array and 'avgb1' is a positive number but when i
> use the formula : result=b1*100/avgb1
> print, result
> , the answer that i get is a negative array.
>
> Whereas if i use the formula : result=b1/avgb1
> print, result * 100
> , then i get a positive array
>
Even without knowing ENVI, the second problem isn't a bug in ENVI.
A integer occupies (in IDL) 16-bit, and therfore covers a range form
-32768 to
32767
anything larger (or smaller) cannot be represented and therefore you
observe an 'overflow', resulting in a negative number.
IDL evalutates your expressinon from left to right, the
overflow occurs after the multiplication with 100.
In the second case the division is done first and thus the value seems
to be small enough not to overflow in the later multiplication.
The solution is to convert your b1 array to LONG.
But did you notice that you do an integer division?
1/2 equals 0.
Maybe you want to use FLOAT or DOUBLE.
hdh,
marc
|
|
|
|
| Re: more bugs in envi !!! [message #35968 is a reply to message #35725] |
Fri, 25 July 2003 02:45 |
David Lopez Pons
Messages: 8
Registered: July 2003
|
Junior Member |
|
|
Answer to your second problem:
I thik that yours is an overflow problem. The resultof the operation
b1*100 it's to big for an interger (integer, I supose) and returns the
negative value.
Maybe the operation 'b1/avgb1*100' (all together, in the same line)
works fine.
Another solution is to force the float operation with a dot: 'b1*100./avgb1'
DLo.
Gaurav wrote:
> Hi folks!
> Sorry to trouble u again....but envi seems to be just going above my
> head...there is another problem that i am facing:
> Please go through the 2 functions:
>
> 1.function example,b1
> help,b1
> end
> 2.function example,b1,b2
> help,b1
> end
>
> Now could anyone tell me why these 2 codes are producing different
> final answers??? I just cant find any reason for it.
>
> One more problem :
>
> 'b1' is a positive array and 'avgb1' is a positive number but when i
> use the formula : result=b1*100/avgb1
> print, result
> , the answer that i get is a negative array.
>
> Whereas if i use the formula : result=b1/avgb1
> print, result * 100
> , then i get a positive array
>
>
> I hope to hear the answers to these questions soon. Thnxx
> Byee
> Gaurav
>
>
|
|
|
|
comp.lang.idl-pvwave archive
Members
Search
Help
Login
Home
