| help with IF statement [message #90059] |
Wed, 21 January 2015 09:26  |
g.nacarts
Messages: 148
Registered: November 2013
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Senior Member |
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Hi
I need some help with an IF statement because I suspect that it's not doing what I really wish to do.
I have a 3D array [120,200,200] which contains my data. Then I am using this matrix to create another matrix. My code looks like this
DataArray ; contains the 3D data
Mean = total(DataArray[0:4,*,*],1)/5.
for i = 0, 199 do begin
for j = 0, 199 do begin
Barray = DataArray[*,i,j] - Array[i,j]
IF (TOTAL(Barray LT 0)) GT 0 THEN NEW_DATA[*,j,k] = Mean[j,k] $
ELSE NEW_DATA[*,j,k] = Mean[j,k] + OTHER
endfor
endfor
What I wanted to achieve with the above is that if an entry in the Barray has a negative value then the New_Data it's equals the mean otherwise NEW_DATA= Mean+ OTHER.
My data are images and when I display the images after that I found out that in places that there are not negative numbers the new_data array equals the mean only not the whole expression (Mean[j,k] + OTHER). Why this happened? It supposed to use the mean only when there are negatives.
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| Re: help with IF statement [message #90062 is a reply to message #90059] |
Wed, 21 January 2015 16:07  |
penteado
Messages: 866
Registered: February 2018
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Senior Member
Administrator |
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If I am reading it right, your code seems to match your description. Someone here used to say that this usually means there is something wrong with your assumptions about your arrays.
I would suggest checking the types, dimensions and values of some of the relevant expressions in your code, such as barray, other, dataarray[*,i,j], array[i,j], new_data[*,j,k] and mean[j,k]
By the way, are the expressions with new_data and mean supposed to be indexed by j and k? Not j and i? There is nothing in this code fragment setting the value of k. If it is really k, check that j and k were not swapped.
Paulo
On Wednesday, January 21, 2015 at 3:26:59 PM UTC-2, g.na...@gmail.com wrote:
> Hi
>
> I need some help with an IF statement because I suspect that it's not doing what I really wish to do.
>
> I have a 3D array [120,200,200] which contains my data. Then I am using this matrix to create another matrix. My code looks like this
>
> DataArray ; contains the 3D data
> Mean = total(DataArray[0:4,*,*],1)/5.
>
> for i = 0, 199 do begin
> for j = 0, 199 do begin
> Barray = DataArray[*,i,j] - Array[i,j]
> IF (TOTAL(Barray LT 0)) GT 0 THEN NEW_DATA[*,j,k] = Mean[j,k] $
> ELSE NEW_DATA[*,j,k] = Mean[j,k] + OTHER
> endfor
> endfor
>
> What I wanted to achieve with the above is that if an entry in the Barray has a negative value then the New_Data it's equals the mean otherwise NEW_DATA= Mean+ OTHER.
> My data are images and when I display the images after that I found out that in places that there are not negative numbers the new_data array equals the mean only not the whole expression (Mean[j,k] + OTHER). Why this happened? It supposed to use the mean only when there are negatives.
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| Re: help with IF statement [message #90064 is a reply to message #90059] |
Thu, 22 January 2015 01:29 |
g.nacarts
Messages: 148
Registered: November 2013
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Senior Member |
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Thanks for your suggestions I will take a look. Just to double check my code
Instead of this IF statement:
IF (TOTAL(Barray LT 0)) GT 0 THEN NEW_DATA[*,i,j] = Mean[i,j] $
ELSE NEW_DATA[*,i,j] = Mean[i,j] + OTHER
Replace it by this:
NEW_DATA[*,j,k] >= Mean[j,k] $
Still doing the same thing right?
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