How can I measure time on MATLAB?

Hi, I am trying to measure the running time of solving system of linear equations using tic , toc. I have to compute the system of linear equation with (A+aI) for different scaler a in one code. How to measure the time of computing the system of linear equations for all a. Do we need to compute the total as I did below or we need to take the average of time?

n=200;
A=full(gallery('tridiag',n,1,2,1));
b=randn(n,1);
tic
[L,U]=lu(A+3*eye(n));
t=L\b;
x=U\t;
time(1)=toc;
tic
[L1,U1]=lu(A+6*eye(n));
t1=L1\b;
x1=U1\t1;
time(2)=toc;
total=time(1)+time(2);

Answer 1

[David Hill]

n=200;
A=full(gallery('tridiag',n,1,2,1));
a=[3,6];
b=randn(n,1);
for k=1:length(a)
  tic
  [L,U]=lu(A+a(k)*eye(n));
  t(k)=L\b;
  x(k)=U\t(k);
  time(k)=toc;
end
totalTime=sum(time);

[Omar B.]

So, we do not need to calculate the avearge time?

[David Hill]

If you want average time, then:

avgTime=mean(time);

[Omar B.]

Thank you for your help. I was asking what is the best to compute the summation or the avearge time.

[Walter Roberson]

What is "best" depends upon your needs, but mean() or median() is most often the useful measure.

[Omar B.]

Thank you.