I have an equation
y=b*((p+l+k-sqrt((p+l+k)^2-4pl))/2p)
where k and b are adjustable parameters to solve for with given p and l
The y is given from experimental data with this formula
y=sqrt(((x0-xi)/10)^2+(z0-zi)^2)
Where x0 is the first value at concentration ligand=0, and xi is all the other entries in the array (same with z0 and zi, so first entry 0 and all other entries differences from first). The data for x and z are in a series of text files, with p and l coming from the name of the text file.
I first read through all the text files and extract x,z,p, and l. Then I use x and z to calculate y (i.e. csp in my script). Finally, I fit the above function using nlinfit.
I have been told with this data set, you should get solutions from individual fits, but I cannot. I want to ensure that my script is setup correctly and doing what it needs to do, and the issue I am getting from matlab is not from a script setup, but from the data itself. Here is my code:
label=strings(242,numel(titration_files));
for i=1:length(titration_files)
protein_concentration=regexp(titration_files(i).name,'pcna_(\d+\.\d*)','tokens');
ligand_concentration=regexp(titration_files(i).name,'brct_(\d+\.\d*)','tokens');
protein(i)=str2double(protein_concentration{1});
ligand(i)=str2double(ligand_concentration{1});
read_files=readtable(titration_files(i).name);
label(:,i)=convertCharsToStrings(read_files.Assignment);
nitrogen(:,i)=read_files.w1;
hydrogen(:,i)=read_files.w2;
[rows,columns]=size(nitrogen);
csp(i,j)=sqrt(((nitrogen(i,end)-nitrogen(i,j))/10)^2+((hydrogen(i,end)-hydrogen(i,j))^2));
x =[flip(protein.'),flip(ligand.')];
model=@(b,x)((x(:,1)+x(:,2)+b(2))-sqrt((x(:,1)+x(:,2)+b(2)).^2)-(4.*x(:,1).*x(:,2))).*(b(1)./(2.*x(:,1)));
Where the format of the data is (there are of course many more text/data files than this, I just wanted to give an example of the output. So one csp here for example would be for E20N-H csp=sqrt((118.384-118.380)/10)^2+(7.849 -7.838)^2), this would be just one entry for this p and l).
