nonlin_min function

[Steph Bredenhann]

I'll appreciate some help with the nonlin_min function

My code is as follows and the objective function is included as a separate file. My problem is that GPL_x, the column vector of unknowns to be solved is returned as GPL_x0, the seed values.

% initialise the GPL parameters
GPL_x = [0; 0; 0];  % in order D0 D1 m
 
% the first estimate of model parameters
% in the GPL model D(t) = D0 + D1*(t)^m
GPL_D0 = 0.0006; %0.000626249601623718;
GPL_D1 = 0.0001; %0.000107587010307332;
GPL_m  = 0.3     %0.312356329396664;     
 
% D_test = fn_GPL_model (GPL_D0, GPL_D1, GPL_m, BBR_tr)
  
GPL_D  = BBR_D(1,:);
GPL_tr = BBR_tr(1,:);
for ii = 2 : rows(BBR_D)
  GPL_D  = [GPL_D, BBR_D(ii,:)];
  GPL_tr = [GPL_tr, BBR_tr(ii,:)];
endfor
 
fun_GPL = @(GPL_x)fn_BBR_GPL_RMSE (GPL_x, GPL_D, GPL_tr);
%GPL_x0_lb = [1000.0; 1.0e6; 0.1; 0.0];
%GPL_x0_ub = [3000.0; 4.0e6; 0.9; 1.0];
GPL_x0 = [GPL_D0; GPL_D1; GPL_m];
[GPL_x, GPL_RMSE, cvg, outp] =...
   nonlin_min(fun_GPL, GPL_x0);
GPL_D0 = GPL_x(1);
GPL_D1 = GPL_x(2);
GPL_m  = GPL_x(3);
 
I'll appreciate some advice, thank you very much.

--
Steph Bredenhann

fn_BBR_GPL_RMSE.m
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