init

FOTF Toolbox/glfdiff0.m

@@ -0,0 +1,19 @@
+function [df,C]=glfdiff0(f,t,gam)
+% glfdiff0 - evaluation of GL derivatives, not recommended 
+%
+%   dy=glfdiff0(y,t,gam)
+%
+%   y - the samples of the function handle of the original function
+%   t - the time vector
+%   gam - the fractional order
+%   dy - the fractional-order derivatives, or integrals if gam<0
+   
+% Copyright (c) Dingyu Xue, Northeastern University, China
+% Last modified 28 March, 2017 
+% Last modified 18 May, 2022 
+   arguments, f(1,:), t(1,:) double, gam(1,1) double, end
+   [f,h,n]=fdiffcom(f,t);  J=0:(n-1); a0=f(1);
+   if a0~=0 && gam>0, dy(1)=sign(a0)*Inf; end
+   C=gamma(gam+1)*(-1).^J./gamma(J+1)./gamma(gam-J+1)/h^gam;
+   for i=2:n, dy(i)=C(1:i)*f(i:-1:1); end
+end