| ERROR: Attempt to subscript B with is out of range [message #89912] |
Wed, 24 December 2014 03:52  |
g.nacarts
Messages: 148
Registered: November 2013
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Senior Member |
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Hi
I've got a 3D array B[100,200,200]. My array B sometimes contains negative values and other times very large values. In order to make sure that when there are either negative or very large values will set to zero I wrote the following code:
FOR i=0L,199 DO BEGIN
FOR j=0L,199 DO BEGIN
WRONG = total((B[*,i,j] LT 0) OR (B[*,i,j] GT 10000))
IF WRONG GT 0 THEN B[*,i,j]=0
ENDFOR
ENDFOR
I got the error Attempt to subscript B with j is out of range. I cannot figure out with this happen with the j variable. Any idea?
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| Re: ERROR: Attempt to subscript B with is out of range [message #89913 is a reply to message #89912] |
Wed, 24 December 2014 06:28  |
Helder Marchetto
Messages: 520
Registered: November 2011
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Senior Member |
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On Wednesday, December 24, 2014 12:52:13 PM UTC+1, g.na...@gmail.com wrote:
> Hi
>
> I've got a 3D array B[100,200,200]. My array B sometimes contains negative values and other times very large values. In order to make sure that when there are either negative or very large values will set to zero I wrote the following code:
>
> FOR i=0L,199 DO BEGIN
> FOR j=0L,199 DO BEGIN
> WRONG = total((B[*,i,j] LT 0) OR (B[*,i,j] GT 10000))
> IF WRONG GT 0 THEN B[*,i,j]=0
> ENDFOR
> ENDFOR
>
> I got the error Attempt to subscript B with j is out of range. I cannot figure out with this happen with the j variable. Any idea?
Hi,
that's not the IDL way. Here is one way of doing it (didn't check, but I think it is also a lot faster):
;create an array
b = long(randomu(s,100,200,200)*100)
b[50,100,100] = -12
b[51,101,101] = 20000
;look for the bad values
pos = where((a lt 0) or (a gt 10000), cnt)
if cnt gt 0 then b[pos]=0l
There are other ways of doing this sort of search for values in an array. Have a look at older posts.
Cheers,
h
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| Re: ERROR: Attempt to subscript B with is out of range [message #89914 is a reply to message #89912] |
Wed, 24 December 2014 07:00 |
wlandsman
Messages: 743
Registered: June 2000
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Senior Member |
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I don't know why you are getting a subscript error. But have you done any debugging? In particular
1. What line number does the subscript error occur in?
2. What are the values of I and J when the subscript error occurs?
3. Can you confirm that the array B is still dimensioned 100x 200x200 when the error occurs?
Usually, when I have an error that shouldn't occur, it is because one of my assumptions is faulty.
--Wayne
On Wednesday, December 24, 2014 6:52:13 AM UTC-5, g.na...@gmail.com wrote:
> Hi
>
> I've got a 3D array B[100,200,200]. My array B sometimes contains negative values and other times very large values. In order to make sure that when there are either negative or very large values will set to zero I wrote the following code:
>
> FOR i=0L,199 DO BEGIN
> FOR j=0L,199 DO BEGIN
> WRONG = total((B[*,i,j] LT 0) OR (B[*,i,j] GT 10000))
> IF WRONG GT 0 THEN B[*,i,j]=0
> ENDFOR
> ENDFOR
>
> I got the error Attempt to subscript B with j is out of range. I cannot figure out with this happen with the j variable. Any idea?
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| Re: ERROR: Attempt to subscript B with is out of range [message #89921 is a reply to message #89912] |
Sat, 27 December 2014 10:32 |
dg86
Messages: 118
Registered: September 2012
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Senior Member |
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On Wednesday, December 24, 2014 6:52:13 AM UTC-5, g.na...@gmail.com wrote:
> Hi
>
> I've got a 3D array B[100,200,200]. My array B sometimes contains negative values and other times very large values. In order to make sure that when there are either negative or very large values will set to zero I wrote the following code:
>
> FOR i=0L,199 DO BEGIN
> FOR j=0L,199 DO BEGIN
> WRONG = total((B[*,i,j] LT 0) OR (B[*,i,j] GT 10000))
> IF WRONG GT 0 THEN B[*,i,j]=0
> ENDFOR
> ENDFOR
>
> I got the error Attempt to subscript B with j is out of range. I cannot figure out with this happen with the j variable. Any idea?
1. Here's a nice idiom for setting negative values to zero
b = b > 0.
An even more compact version:
b >= 0.
2. Masking large values similarly is quick and easy
threshold = 10000
b = b * (b le threshold)
The more compact version is
b *= b le threshold
Summarizing the quick way to achieve your goals
b >= 0. ; set negative values to zero
b *= b le threshold ; set large values to zero
TTFN,
David
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