ec50.m

可以进行曲线回归拟合算法的四参数算法。函数为 y = (a-d)/(1+(x/c)^b) +d . ec50.m 为其主要函数

function results=ec50(conc,responses)
% EC50 Function to fit a dose-response data to a 4 parameter dose-response
%   curve.
% 
% Requirements: nlinfit function in the Statistics Toolbox
%           and accompanying m.files: init_coeffs.m and sigmoid.m
% Inputs: 1. a 1 dimensional array of drug concentrations
%         2. the corresponding m x n array of responses 
% Algorithm: generate a set of initial coefficients including the Hill
%               coefficient
%            fit the data to the 4 parameter dose-response curve using
%               nonlinear least squares
% Output: a matrix of the 4 parameters
%         results[m,1]=min
%         results[m,2]=max
%         results[m,3]=ec50
%         results[m,4]=Hill coefficient
%
% Copyright 2004 Carlos Evangelista 
% send comments to [e-mail]
% Version 1.0    01/07/2004
%conc = conc';
%responses = responses';
[m,n]=size(responses);
results=zeros(n,4);
for i=1:n
     response=responses(:,i);
     initial_params=init_coeffs(conc,response);
     [coeffs,r,J]=nlinfit(conc,response,'sigmoid',initial_params);
%    disp (coeffs);
     for j=1:4
         results(i,j)=coeffs(j);
     end
end
%disp (results);