Hello I am very new user of qt octave and trying to fit my function to the experimental data......in my data I have transmission at given wavelength and for given thickness..... for 10 thcikness i want to calculate absorption length and transport mean free path.....using mention input i want to fit my data in photonic ohms law
I have some doubts 1. HOW to call the function in qt octave? 2. I am getting the error that leasqr is not defined.... 3. its an itarative program so its not asking for input and then some comment that "fit" is not defined.....
Here I am sending you my code for ohms law and function.... OHMS_law ....................................................................................................................................................................................................................................................................
load("-ascii", "/home/gaikwad/Bureau/for octave/FinalTiO2.dat", "") %put here the file name you want to load fname = FinalTiO2; lambda = fname(:,1) ; nr=size(fname,1); nc=size(fname,2)-1;
T=fname(:,2:1+nc); % thickness vector L = [72 80 91 100 107 108 150 181 223 265 268 350]; x = L-50; %um thickness correction due to the air bubble y=1./T(1,:); %% initial values: pin = [0.5 250];% ls;la
options.bounds=[0 5;100 500]; %% other configuration (default values): tolerance = .0001; max_iterations = 100; weights = ones (1, nc); dp = [.001; .001]; % bidirectional numeric gradient stepsize dFdp = 'dfdp'; % function for gradient (numerical)
figure(100) contourf(L,lambda,log(abs(1./T))) ylabel('Wavelength [nm]','FontSize',14) title(' 1/ Total transmission - log scale','FontSize',14) xlabel(' Thickness L [um]','FontSize',14)
colormap("default") caxis([0 6]) colorbar
% data fitting lmax=length(lambda); lmin = 1; lambda = lambda([lmin:lmax]);
%--lambda fit loop ------------------------------------------------------
for i=lmin:lmax % i is the LAMBDA VARIABLE
%all points are used y=1./T(i,:); %% start leasqr, be sure that 'verbose' is not set global verbose; verbose = 1; [f, p] = leasqr(x, y, pin,trans_fnc.m , tolerance, max_iterations, weights, dp, dFdp, options.bounds);
ls(i) = p(1); la(i) = p(2); fit(i,:) = f;
end %--end of lambda fit loop ---------------------------------------------
%% -plot and save figure(31) plot(lambda, ls,'.')
xlabel(' Wavelength [nm]','FontSize',14) ylabel('Transport m.f.p. [um]','FontSize',14) title(' Scattering length from the fit ','FontSize',14) % axis([0 1200 1 1.5 ])
figure(32) plot(lambda, la,'r.') xlabel(' Wavelength [nm]','FontSize',14) ylabel('Transport m.f.p. [um]','FontSize',14) title(' Absorption length from the fit ','FontSize',14)
% axis([0 1200 1 1.5 ])
%-Ohm's law plot-------------------------------------------------------
figure(1) plot(x,1./T(166,:),'*') hold on plot(x,1./T(195,:),'ro')
plot(x,fit(166,:),'b') plot(x,fit(195,:),'-r') hold off xlabel(' Thickness L [um]','FontSize',14) ylabel('1/Transmission [1/%]','FontSize',14)
title(' 1/ Total transmission - lambda cut','FontSize',14) %axis([0 1600 1 100 ]) legend('lambda = 824 nm','lambda = 876 nm','FontSize',14) ____________________________________________________________________________________________________________________________________________________
Function
function F = trans_fnc(x,p) % Diffusive time-decay profile if nargin~=2 error('This function is waiting for 2 arguments') end
ls = p(1); % in um la = p(2);% in um
offset = 0.0; c=0.3; %speed of light in um/fs n1 = 2.1; % average refractive index n2 = 1; R = 0.52; % average reflection on the interface from PRA 44, 3948 (1991) %Rz = (n1-n2)/((n1+n2)^2);
z0 = (2/3)*ls*(1+R)/(1-R); ze = (la/2)*log((1+(1/la)*z0)/(1-(1/la)*z0)); zp = ze; %% model function: F=1.0./( (la/ze)*sinh((zp+ze)/la)*sinh(ze/la)./sinh(((x+offset)+2*ze)/la)); % inverse transmittance ________________________________________________________________
thanks a lot in advance for your help