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Replies: 3   Last Post: Nov 24, 2012 9:30 AM

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 ARTEMIS CIVIL Posts: 3 Registered: 11/23/12
Posted: Nov 24, 2012 9:13 AM

dpb <none@non.net> wrote in message <k8ot2s\$sqj\$1@speranza.aioe.org>...
> 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.
>
> --

thanks a lot for the help! (sorry for the threads...I am a new follower of this site!)
I would like to ask you one more question:
Previously, I had the code and a parameter "n" as an input in order to find the parameter Pu: output! Now, from experiments I know the real value of the parameter Pu, is it possible to find from the code the parameter n ( as an output) if I give the Pu as an input? could I "invert" the code?? Thanks in advance!

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