Initial conditions in a fitting

Hello everyone

I'm trying to figure out the impact of boundary conditions on a fitting. The file where my fitting is defined looks like:

function [fitresult,gof]=Fitting(space,magnetization,initial_magnetization,initial_conditions)
if round(initial_magnetization(1),1)==0.7 && round(initial_magnetization(end),1)==0.7
    fitting_function='(1/sqrt(2))*(sin(atan(exp(Q*(x-x0)/Delta)))+cos(atan(exp(Q*(x-x0)/Delta))))';
elseif round(initial_magnetization(1),1)==-0.7 && round(initial_magnetization(end),1)==-0.7
    fitting_function='-(1/sqrt(2))*(sin(atan(exp(Q*(x-x0)/Delta)))+cos(atan(exp(Q*(x-x0)/Delta))))';
elseif round(initial_magnetization(1),1)==-0.7 && round(initial_magnetization(end),1)==0.7
    fitting_function='(1/sqrt(2))*(sin(atan(exp(Q*(x-x0)/Delta)))-cos(atan(exp(Q*(x-x0)/Delta))))';
elseif round(initial_magnetization(1),1)==0.7 && round(initial_magnetization(end),1)==-0.7
    fitting_function='-(1/sqrt(2))*(sin(atan(exp(Q*(x-x0)/Delta)))-cos(atan(exp(Q*(x-x0)/Delta))))';
end
ft=fittype(fitting_function,'independent','x','dependent','y');
opts=fitoptions('Method','NonlinearLeastSquares');
opts.Display='Off';
opts.StartPoint=initial_conditions;
[fitresult,gof]=fit(space,magnetization,ft,opts);

On the other hand, in the file where I process the data I have the following:

    % Initial conditions
    Initial_Conditions=[Delta0 x0_Q Topological_Charge(1)];
    % Let's apply the fitting to the mx component
    for j=1:length(Time)
        [fitresult,gof]=Fitting(Spatial_Grid,mx(:,j),mx(:,1),Initial_Conditions);
        Delta_Q(j)=fitresult.Delta; % m
        x0_Q(j)=fitresult.x0; % m
        Initial_Conditions=[Delta_Q(j) x0_Q(j) Topological_Charge(j)];
    end
   

I was wondering on which order I have to write the initial conditions (Delta0, x0_Q, Topological_Charge), to match what it is defined in the function Fitting. It is important to note that Delta0/Delta_Q corresponds to Delta, x0_Q to x0, and Topological_Charge to Q in the fitting function environment. That is, as, for example:

    Initial_Conditions=[Delta_Q(j) x0_Q(j) Topological_Charge(j)];
    Initial_Conditions=[x0_Q(j) Delta_Q(j) Topological_Charge(j)];
    ...

Answer 1

[Walter Roberson]

coeffnames(ft)

will tell you the names of the model coefficients. The order they are displayed in is the same order as you should use for the initial values.