Matlab-数据拟合子程序

可自行设置拟合多项式形式

直接调用即可

调用格式：

[PPb5_xi,PPb5_yi]=Poly_Drizzly(PPb5_x, PPb5_y);

子程序：

function [xi, yi] = Poly_Drizzly1(x, y)

%已知函数，示例顺序为：函数， 'independent', 自变量名，'coefficients'， {变量名}；

f = fittype(' a * PPb_x + b', ...

'independent', 'PPb_x', 'coefficients', {'a', 'b'});

cfun = fit(x, y, f, 'StartPoint', [0, 0]);

xi = min(x) : (max(x)-min(x))/30 : max(x);

yi = cfun(xi);

end

 

function [xi, yi] = Poly_Drizzly2(x, y)

%已知函数，示例顺序为：函数， 'independent', 自变量名，'coefficients'， {变量名}；

f = fittype('c * PPb_x^2 + a * PPb_x + b', ...

'independent', 'PPb_x', 'coefficients', {'c','a', 'b'});

cfun = fit(x, y, f, 'StartPoint', [0, 0, 0]);

 

xi = min(x) : (max(x)-min(x))/30 : max(x);

yi = cfun(xi);

end

 

function [xi, yi] = Poly_Drizzly3(x, y)

%已知函数，示例顺序为：函数， 'independent', 自变量名，'coefficients'， {变量名}；

f = fittype('d * PPb_x^3 +c * PPb_x^2 + a * PPb_x + b', ...

'independent', 'PPb_x', 'coefficients', {'d','c','a', 'b'});

cfun = fit(x, y, f, 'StartPoint', [0, 0, 0, 0]);

 

xi = min(x) : (max(x)-min(x))/30 : max(x);

yi = cfun(xi);

end