Search All of the Math Forum:

Views expressed in these public forums are not endorsed by NCTM or The Math Forum.

Notice: We are no longer accepting new posts, but the forums will continue to be readable.

Topic: iterations adjustments UPDATED
Replies: 3   Last Post: Nov 24, 2012 9:30 AM

 Search Thread: Advanced Search

 Messages: [ Previous | Next ]
 dpb Posts: 9,850 Registered: 6/7/07
Re: iterations adjustments UPDATED
Posted: Nov 23, 2012 5:23 PM
 Plain Text Reply

On 11/23/2012 3:32 PM, ARTEMIS CIVIL wrote:
> Hello, I really have to deal with the problem below. I am a beginner in
> matlab and my deadline is quite pressing. Thank you in advance!
> Well, I have to guess an initial value "n" in order to find the ultimate
> value
> "Pu". When the extracting Pu deviates from a specific defined value (Pe)
> more
> than 0.1% then I need the code to make use of the last value of "Pu" to
> find the correct n until the parameter "Pu"reach the Pe. Otherwise the
> parameter n is kept.
> such as:
> input: n
> results: Pu
> target: pe
> dp=pu-pe
> if dp<0.1% keep n
> or else n=n+dn and again from the begining until the Pe is reached!
> Thanks!!

Better to not keep making new threads, also...

You've gone to the other extreme now w/ perhaps too little, but

Enclose the computation in a WHILE loop, initializing the error to a
large value--

dp=inf; % initialize difference to big number
err=0.1; % set an error criterion
n=n0-dn; % initialize n
while dp>err
...
n=n+dn;
% compute here
dp=pu-pe;
end

This will stop the loop when the error criterion is met w/ the value of
n that satisfied it by having the n+dn term before the computation.

--

Date Subject Author
11/23/12 ARTEMIS CIVIL
11/23/12 dpb
11/24/12 ARTEMIS CIVIL
11/24/12 dpb

© The Math Forum at NCTM 1994-2018. All Rights Reserved.