Several loops in Matlab

Hi,

Can matlab calculate only the first iteration (i=1) of the loop1 and get out of the loop to compute the first iteration for the secod loop?

is there a way to do that?

example:

for i=1:N

A(i)=a*B(i)

end

for i=N:-1:1

B(i)=......

end

[Alex Mcaulley]

Do you mean this?

break function

Answer 1

[Jan]

A break can stop a loop prematurely:

for i = 1:N
  A(i) = a*B(i);
  break;
end
for i = N:-1:1
  B(i) = rand;
end

But this seems to be to indirect. If you want to run the first iteration of the first loop only, write this explicitely:

A(1) = a = B(1);

Do not create a loop, if you do not want to run it.

Which is the actual problem you want to solve?

[m m]

i need to create loop, i want to run the first iteration from the first loop, then, the first iteration from the second ... then, the second iteration from the first loop.. the second from the second loop....etc.

is it possible ?

[Jan]

This would be extrem confusing. It sounds like you want to run both commands in one loop:

for i = 1:N
  A(i) = a*B(i)
  j = N - i + 1;
  B(k) = rand;
end

[Jan]

Sorry, I'm unable to read this code because the pile of lowercase characters disturb my eyes. I do not understand the mutual dependencies and the dynamic indentation scheme is tedious also.

Why do you waste time and energy with writing:

E=V(i+1)-V(i);
A=V(i+1)-V(i)/2;
B=V(i)-V(i-1)/2;
je=(ne(i+1) - ne(k,i).*exp(Te1).*Te1)./((dx);

if the values are not used anywhere? What is "k" here? And in addition, this code will not even run due to a missing trailing parenthesis.

Please post clean and clear running code. Remove unused code sections and press Ctrl-a Ctrl-i to get a proper indentation.

Omit such code inside a loop:

ap(i)= 1;
bp(i)= -2;
cp(i)= 1;
dp(i)= -(ni(i)-ne(i));

if you can do this easily outside:

ap = ones(1, nx - 1);
bp = repmat(-2, 1, nx - 1);
cp = ones(1, nx - 1);
dp = ne - ni;