Yes, you can do it with while as well. I suggest ready the help for while and the Getting Started with MATLAB documentation for more information.

–Loren

what happened when there are multiple options like:

t = 11;
a = 5;
i = 0;
repeat
inc(i);
until (i = 5) or (t > a)

Will it be handled with “while” only?

Regards

Since you can compute the steps in advance, you would be best off using a for loop, something like

for count=4:2:20
   doStuff
end

–Loren

begin
   Count := 4;
   repeat
      Write('This is in the ');
      Write('repeat loop, and ');
      Write('the index is',Count:4);
      Writeln;
      Count := Count + 2;
   until Count = 20;
   Writeln(' We have completed the loop ');
end.

I suggest you read the help for for more carefully. And also look for the help for the colon operator. You can assign anything to the loop counter, including a vector that decreases, e.g., 10:-1:1.

–Loren

what i need to do in for is:

temp = aif(I);
for v = I:1
if(aif(v)>temp)
temp=aif(v);
v = v-1;
else
arr = aif(v);
disp(arr);
end
end
how do i replace the for loop here?

You have not provided enough information for me to have any insight. I recommend you contact support (link on the right side) with more details and they will help you out. Off-hand, for and while loops are neither worse nor better than each other – but used for different purposes typically.

The profiler, M-Lint, and the last 3 sections of the MATLAB documentation under Programming Fundamentals:

http://www.mathworks.com/access/helpdesk/help/techdoc/matlab_prog/bqjgwp9.html

have a lot of advice for code optimization.

–Loren

I wrote a program for processing images of size 4008 x4008.

When i executed the code,the code runs for almost 2 days.Also if i change the input data as 8-bit,i do get a result but if i give the original 16-bit data as input..an error is thrown stated as out of memory exception.(Help memory)..

Actually i need several instances of the image and there was an inherent need to use several for loops.Could this cause a overhead.( it suggested me to consider preallocating for speed but there is a memory limitation along with the speed).

so i am wondering if while is better than for loop.?

I would appreciate if you could give me a light on this part.It would be great if Matlab could provide few materials about code optimization in Matlab.

What you may need to do is to set a variable in the inner loop (switch between true and false if you break). In the outer loop, check to see if the inner loop broke or not and act accordingly.

–Loren