for loop

how to use 'for' in a nested loop and get a result quickly for example I write this code:
%%%%%%%%%%%%%%%%%%
Ac=reshape(Ac,1,[]);
Ac_estm=reshape(Ac_estm,1,[]);
P=size(Ac,2);
T=reshape(T,1,[]);
for(p=1:P)
delta=d*Ac(p);
if(T(p)==0)
while(Ac(p)<=Ac_estm(p)-delta)
Ac(p)=Ac(p)-1;
end
else
while(Ac(p)>=Ac_estm(p)+delta)
Ac(p)=Ac(p)+1;
end
end
end
%%%%%%%%%%%%%
but the execution is very slow and stops over the counter at 9
(T is logical and length(T)>= length(Ac) and length(Ac)=length(Ac_estm))

4 Comments

Andrei Bobrov
Andrei Bobrov on 27 Apr 2011
divergent process
while(Ac(p)<=Ac_estm(p)-delta)
Ac(p)=Ac(p)-1;
end
...
while(Ac(p)>=Ac_estm(p)+delta)
Ac(p)=Ac(p)+1;
end
samia
samia on 27 Apr 2011
why it's divergent process since p=1 to P??
Andrei Bobrov
Andrei Bobrov on 27 Apr 2011
while(Ac(p)<=Ac_estm(p)-delta)
Ac(p)=Ac(p)-1;
end
here perhaps Ac(p)-> -inf
while(Ac(p)>=Ac_estm(p)-delta)
Ac(p)=Ac(p)+1;
end
and here perhaps Ac(p)-> +inf
Andrei Bobrov
Andrei Bobrov on 27 Apr 2011
use variant
while(Ac(p)<=Ac_estm(p)-delta)
Ac(p)=Ac(p)+1;
end
while(Ac(p)>=Ac_estm(p)-delta)
Ac(p)=Ac(p)-1;
end

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 Accepted Answer

Andrei Bobrov
Andrei Bobrov on 27 Apr 2011

0 votes

variant without loop
delta = d*Ac;
t = T==0;
R = Ac - Ac_estm;
R1 = R + delta;
R2 = R - delta;
t1 = sign(R1) <= 0;
t2 = sign(R2) >= 0;
Ac(t & t1) = Ac(t & t1) + ceil(abs(R1(t & t1)));%changed sign
Ac(~t & t2) = Ac(~t & t2) - ceil(abs(R2(~t & t2)));%changed sign
variant with loop
Ac=reshape(Ac,1,[]);
Ac_estm=reshape(Ac_estm,1,[]);
P=size(Ac,2);
T=reshape(T,1,[]);
for p=1:P
delta=d*Ac(p);
if T(p)==0
t = Ac(p) - Ac_estm(p) + delta;
t1 = t(t<=0);
else
t = Ac(p) - Ac_estm(p) - delta;
t1 = t(t>=0);
end
Ac(p) = Ac(p) - sign(t1)*ceil(abs(t1));
end

1 Comment

samia
samia on 28 Apr 2011
thank you for your aid!!

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