dpb <firstname.lastname@example.org> wrote in message <email@example.com>... > 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!