Similar lines are much different in time for run due to MATLAB profiler.

The right hand side of all of below equation are numbers (in same order of magnitude) but the first line is much slower. Any idea why this is happening? The image of profile is also attached.

% Comp.Yp(j,1)=Yp;
% Comp.Yp1(j,1)=Yp1;
% Comp.Yp2(j,1)=Yp2;
% Comp.Yt(j,1)=Yt;
% Comp.Y_sh(j,1)=Y_sh;
% Comp.Y_Ex(j,1)=Y_Ex;

[Rik]

Can you give a bit more context?

[hosein bashi]

I have a very big code. I do not know much about using classes but using class definition helped me making the code more neat. So I used static method to have functions in different classes to remmeber functions and find them quickly when they are neatly organized. here is a part of one of the satic method function:

function [Comp]=Loss_SL(Comp,QO,n,j,Nmid)

%input:Geometry;betaBC1;Machr1,2;alphaBC1,2;

sc=Comp.G.sc(j,1);

c=Comp.G.c(j,1);

s=sc.*c;

o=Comp.G.o(j,1);

e=Comp.G.e(j,1);

te=Comp.G.te(j,1);

t=Comp.G.t(j,1);

sRc=Comp.G.sRc(j,1);

.....

Doing many Calculations whith above parameters and compute Yp,Ys, ... and save them in Comp object:

....

Comp.Yp(j,1)=Yp;

Comp.Yp1(j,1)=Yp1;

Comp.Yp2(j,1)=Yp2;

Comp.Yt(j,1)=Yt;

Comp.Y_sh(j,1)=Y_sh;

Comp.Y_Ex(j,1)=Y_Ex;

[Philip Borghesani]

You are calling this funciton quite a few times. Without more understanding of your code it is unlikely that a good anwer can be supplied. Some questions and things to think about:

1. Is your object a handle or value object? If it is simple give some info about it or the code.
2. How are you calling this function? what are the inputs and outputs?
3. Are your members (Yp1,Yp2,...) preallocated?

Most likely the best way to improve your code is to restructure it so that the helper function can be vectorized and not called so many times.

Answer 1

[Fangjun Jiang]

It takes time to create "Comp" as a structure. Add the line below first and then profile again.

Comp=struct;

[hosein bashi]

Thank you. But as I explained for Rik in previous comment the Comp is an object which is input (and output) of a function. so I think it's previously an structure.

Answer 2

[Philip Borghesani]

Most likely this is happining due to memory allocation, caching and array growth. Unfortunatly this answer wont help you much.... See my comments to your question