From: Help-octave <help-octave-bounces+steph=address@hidden> On Behalf Of Steph Bredenhann
Sent: Monday, April 06, 2020 12:08
To: Kai Torben Ohlhus <address@hidden>
Cc: address@hidden
Subject: Re: nonlin_min function
On 2020/04/06 10:54, Kai Torben Ohlhus wrote:
On 4/6/20 2:49 PM, Steph Bredenhann wrote:
[...]
The variables are as follows, and please note that the values after %
for GPL_Do, etc are the values as calculated with Excel SOLVE function:
[...]
Dear Steph,
I attached all necessary codes as m-files.
Maybe there is a typo in your function "fn_BBR_GPL_RMSE()"? In short:
Dcalc = D = D0 + D1*t.^m;
SRE = (D-Dcalc)./D;
In this case "SRE" is always zero, as "Dcalc = D" and no progress seems
to happen. Furthermore "D" seems to be an input parameter of
"fn_BBR_GPL_RMSE()", which is unused then.
HTH,
Kai
Thank you very much for taking time to look at my problem, it is appreciated.
There is a typo in my code, it is embarising! I actualy have another function to calculate the GPL D0 + D1*t^m but didn't want to confuse the issue so I replaced the function call with the one line code and then made the typo, my apologies. Removing the typo does not solve my problem, the line should be
Dcalc = D0 + D1*t.^m;
I have added a print statement to print the output of the function fn_BBR_GPL_RMSE:
fn_GPL: RMSE = 1.76664
fn_GPL: RMSE = 1.76566
fn_GPL: RMSE = 1.76762
fn_GPL: RMSE = 1.76433
fn_GPL: RMSE = 1.76895
fn_GPL: RMSE = 1.75902
fn_GPL: RMSE = 1.77424
fn_GPL: RMSE = Inf
fn_GPL: RMSE = 64468270468788378205787493575484047335386768972351487380052923633120701124491032255846390698082304.00000
fn_GPL: RMSE = 128499488.88036
fn_GPL: RMSE = 61955.28569
fn_GPL: RMSE = 602.30488
the search should be for the min of RMSE, it oscillates (because I start very close to the min as determined by Excel) and then suddenly gets out of control.
Yet, on return nonlin_min still report a successful completion, with one iteration?
VE_BBR: GPL_cvg = 3.00000
>> GPL_outp
GPL_outp =
scalar structure containing the fields:
user_interaction =
scalar structure containing the fields:
stop = [](0x1)
info = {}(0x1)
niter = 1
nobjf = 6
I am not experienced with nonlin_min and chances are that I misunderstand something.
Kind regards
Steph
Dear Kai
I didn’t attach the two files to my previous email, for completeness, here they are:
call_script.m