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field displacement array range

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katarado
katarado on 19 May 2017
Edited: katarado on 3 Jun 2017
Hello,
weather1618 and whether1623 are two 2D array of size 384x384. Following is my script section for weather1618Modified for which I tried to do a field displacement. If it helps, max_displ has a value of 139.7.
I do not get any error message when I run the script but I also don't get any value for bestDx and bestDy, the variables don't even create, What am I doing wrong?
%%Find Dx Dy for max_corr between two maps
maxCoeff=0;
weather1618Modified = zeros(384,384); %create weather array for time range
%weather1618Modified(:) = {NaN}; %Matlab cannot mix cell& double
for x = 1:384
for y = 1:384
for Dx = -max_displ:9: max_displ %139.7*2/30= 9 for a 30pixel appx.
for Dy = -max_displ:9: max_displ
%MAKE SURE x+Dy and y+DY don't exceed 1:384
if x+Dx<1 | y+Dy<1 | x+Dx>384 | y+Dy>384
continue
%weather1618Modified is the forecasted weather1823
weather1618Modified(x+Dx,y+Dy) = weather1618(x,y)
%Find the best correlation; Is corrcoef the right formula?
newCoeff=corrcoef(weather1623,weather1618Modified);
if newCoeff>maxCoeff
maxCoeff=newCoeff;
bestDx=Dx;
bestDy=Dy;
end
end
end
end
end
end
  2 Comments
katarado
katarado on 19 May 2017
x sould not go outside that inverval : It shoudn't be less than 1 and not more than 384. I am mostly asking for x+Dx and y+Dy (of the new array). It is now edited for clarity, thank you.

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Accepted Answer

Abhinav Gurram
Abhinav Gurram on 22 May 2017
From the code you have provided, it looks like the set of statements for setting 'maxCoeff', 'bestDx' and 'bestDy' is never reached. If you look closely, the MATLAB Code Analyzer mentions that the line:
weather1618Modified(x+Dx,y+Dy) = weather1618(x,y)
and possibly the following lines, cannot be reached. This is because these statements are placed after the 'continue' and therefore, never get executed. To know more about how to use continue, please visit: Continue documentation - with examples
Another thing to keep in mind is that when 'continue' is used within nested loops, it only skips the remaining statements in the body of the loop in which it occurs. Therefore, you might want to consider enclosing these set of statements in an 'else' condition.
Hope this helps!
  2 Comments
katarado
katarado on 3 Jun 2017
also, where and how can I use the MATLAB Code Analyzer?

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More Answers (1)

Jan
Jan on 22 May 2017
The continue statement prevents the code from creating any variables.
for Dy = -max_displ:9: max_displ
if x+Dx<1 | y+Dy<1 | x+Dx>384 | y+Dy>384
continue
x = 0
end
end
Here x=0 is not reached, because the continue forwards the execution directly to the next iteration. I assume you simply want to omit this command.

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