vector=[];
vectorx=[];
index=1;
for i=100:100:1000
    
    A=rand(i,i);
    v=rand(i,1);
    t1=clock;
    matvec(A,v);
    t2=clock;
    t=etime(t2,t1);
    vector(index)=t;
    
    vectorx(index)=i;
    
    index=index+1;
end
plot(vectorx,vector)