# How to pass control from one loop to the other loop

2 views (last 30 days)
Sai on 14 Oct 2015
Edited: Stephen23 on 16 Oct 2015
My aim is to alter a data sample in such a way that the sign of values in between 0.01 to next 0.01 are altered.
Like for example; if given sample is
{0.3,0.21,0.9,0.3,0.01,0.3,0.4,0.32,0.01,0.9,0.97}
My code has to give the output as
{0.3,0.21,0.9,0.3,0.01,-0.3,-0.4,-0.32,0.01,0.9,0.97}
So, I'm trying to write a nested loop to read the sample and alter the sign in between 0.01 to next 0.01
for n=1:100000
if u(n)=0.01
for m=n+1:10000
if u(m)=0.01
% switch to the original 'n' loop
end
u(m)=-1*u(m);
end
end
end
But, I'm unable to switch to the original loop. Anyone suggest, how can I switch between them ?

Thorsten on 14 Oct 2015
Edited: Thorsten on 14 Oct 2015
invert = 1;
for i = 1:numel(u)
if u(i) == 0.01
invert = -invert;
elseif invert<0
u(i) = -u(i);
end
end
Sai on 15 Oct 2015

Eng. Fredius Magige on 14 Oct 2015
try this
for n=1:100000 if(find(sample(:)==0.01,1)=<find(sample(:)==0.01,2)) % sample is your data num=-1*sample(:,n) else num=sample(:,n) end
Sai on 15 Oct 2015
Thanks for your suggestion :). It worked

Stephen23 on 14 Oct 2015
Edited: Stephen23 on 14 Oct 2015
There is no need for slow and inefficient loops when code vectorization is faster and neater:
>> tol = 0.0005;
>> val = 0.01;
>> V = [0.3,0.21,0.9,0.3,0.01,0.3,0.4,0.32,0.01,0.9,0.97];
>> idx = abs(V-val)<tol;
>> idy = mod(cumsum(idx),2);
>> idz = (-1).^(idy&[false,idy(1:end-1)]);
>> V.*idz
ans =
0.3 0.21 0.9 0.3 0.01 -0.3 -0.4 -0.32 0.01 0.9 0.97
Sai on 15 Oct 2015
Stephen23 on 16 Oct 2015
Edited: Stephen23 on 16 Oct 2015
My pleasure. You can also vote for answers that introduce you to new concepts!

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