field displacement array range

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

[Jan]

How could "x [...] not cross the interval 1 to 384", when it is created by "for x = 1:384"? I do not understand the question in consequence.

[katarado]

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.

Answer 1

[Abhinav Gurram]

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!

[katarado]

thank you for your answer! I tried both using an else statement and putting the "end" directly under the "continue" line but it does not work

[katarado]

also, where and how can I use the MATLAB Code Analyzer?

Answer 2

[Jan]

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.