www.gusucode.com > curvefit 案例源码程序 matlab代码 > curvefit/FindCoefficientOrdertoSetStartPointsandBoundsExample.m
%% Find Coefficient Order to Set Start Points and Bounds % For the properties |Upper|, |Lower|, and |StartPoint|, you need to find % the order of the entries for coefficients. % Copyright 2015 The MathWorks, Inc. %% % Create a fit type. ft = fittype('b*x^2+c*x+a'); %% % Get the coefficient names and order using the |coeffnames| function. coeffnames(ft) %% % Note that this is different from the order of the coefficients in the % expression used to create |ft| with |fittype|. %% % Load data, create a fit and set the start points. load enso fit(month,pressure,ft,'StartPoint',[1,3,5]) %% % This assigns initial values to the coefficients as follows: |a = 1|, % |b = 3|, |c = 5|. %% % Alternatively, you can get the fit options and set start points and lower % bounds, then refit using the new options. options = fitoptions(ft) options.StartPoint = [10 1 3]; options.Lower = [0 -Inf 0]; fit(month,pressure,ft,options)