This makes me very happy! I am glad to see you are able to adopt the ideas and improve your code immediately.

Thanks for watching,

Doug

Happy new year Doug. To get you prepared for the year ahead, I have an incredibly sexy question which eagerly awaits your touch:

Basically I have one function and within it is a nested function:

function func1()
….
function func2()
….
end
….
end

now, within func1 I use another function (non-nested) which I wish to use to mathematically optimise func2. Now, this gives me error messages, since, it would seem this optimisation function is not able to access func2 since it is a nested function.

Now, one solution would be for me to make func2 non-nested and write it out in its own separate m-file and then call the optimisation routine from within func1 to optimise the now-non-nested func2. However, this seems like a non-memory efficient kinda way to do this as, I am gonna have to pass so many arguments to func2 (which in its previously nested state were accessible directly without the need to pass).

Can you help?

BTW, can we also use pointers in MATLAB? Or do we always need to get functions to return everything we want? (Arguments passing by reference etc..)

You are doing a great job with your videos, they are very helpful especially for beginners like me.

Altino

It looks like you are spending 22 hours on this one function, but you are calling it so often that each call is 0.001 seconds. My guess is this is actually quite efficient. Maybe your algorithm can be changed to call ismember.m less often? ismember.m has some decisions internally to decide which algorithm to use based on the lengths of the inputs. You might be able to tweak these.

My other suggestion is this looks like a problem that might call for a computer cluster. You can really cut down on the time needed by using more computing power. Check out the Parallel Computing Toolbox.

Doug

here is segment of the code :

function IncludeInRjPixel_1(ind) %horizontal & vertical
global Wr pxl kls rw cpt;
flag = 0;
% cpt = 0;
f = 0;
while cpt index of image matrix
case 1
ind = ind + 1;
case 2
ind = ind - rw;
case 3
ind = ind + rw;
end;
if f >=4
break;
end;
end;
includePixel(pxl); % calculate average of pixel value of index stored in pxl

this code is called very often until computation is complete

so i can’t make this calculation once. so what do you think of this case sir?

thanks sir for your reply

best regard

adnyana

This is great. Now, all I need to know is “What are the typical values of:

ind
kls
pxl

Are these scalars, vectors, matrices? What are the typical sizes. Do the values change often? If they do not change, can you make these calculations once and then store the value?

Doug

http://img151.imageshack.us/img151/2596/profilersp5.jpg

is there other way or other function that run faster than ‘ismember’.

i use ‘ismember’ function to check if one set of data is member of other set, like this :

ismember(ind,kls)== 1 && ismember(ind,pxl) == 0

thanks a lot sir for helping me

best regard

adnyana

I think that you would want to run the profiler on this code, it will tell you where the slow parts are. From there, we could figure out how to speed it up.

profiler:
http://blogs.mathworks.com/pick/2006/10/19/profiler-to-find-code-bottlenecks/

Doug