 function Fvals = CSeval(F,T,tvals)
% F is a structure: F('a',***,'b',***)
% F.a is a length m+1 column vector, F.b is a length m-1 column vector,
% T is a positive scalar, and tvals is a column vector.
% If 
%   F(t) = F.a(1) + F.a(2)*cos((2*pi/T)*t) +...+ F.a(m+1)*cos((2*m*pi/T)*t) +
%                   F.b(1)*sin((2*pi/T)*t) +...+ F.b(m-1)*cos((2*m*pi/T)*t)
%		   
% then Fvals = F(tvals).

 Fvals = zeros(length(tvals),1);
 tau = (2*pi/T)*tvals;
 for j = 0:length(F.a)-1, Fvals = Fvals + F.a(j+1)*cos(j*tau); end
 for j = 1:length(F.b),   Fvals = Fvals + F.b(j  )*sin(j*tau); end
