gusucode.com > symbolic工具箱matlab源码程序 > symbolic/@sym/ifourier.m
function f = ifourier(F,varargin) %IFOURIER Inverse Fourier integral transform. % f = IFOURIER(F) is the inverse Fourier transform of the symbolic % expression or function F with default independent variable w. If % F does not contain w, then the default variable is determined by % SYMVAR. By default, the result f is a function of x. If F = F(x), % then f is returned as a function of the variable t, f = f(t). % % By definition, % f(x) = abs(s)/(2*pi*c) * int(F(w)*exp(-s*i*w*x),w,-inf,inf). % % You can set the parameters c,s to any numeric or symbolic values % by setting the preference SYMPREF('FourierParameters',[c,s]). % By default, the values are c = 1 and s = -1. % % f = IFOURIER(F,u) returns f as a function of the variable u % instead of the default variable x: % f(u) = abs(s)/(2*pi*c) * int(F(w)*exp(-s*i*w*u),w,-inf,inf). % % f = IFOURIER(F,v,u) treats F as a function of the variable v % instead of the default variable w: % f(u) = abs(s)/(2*pi*c) * int(F(v)*exp(-s*i*v*u),v,-inf,inf). % % Examples: % syms t u v w f(x) % ifourier(w*exp(-3*w)*heaviside(w)) returns 1/(2*pi*(-3+x*1i)^2) % ifourier(1/(1 + w^2),u) returns exp(-abs(u))/2 % ifourier(v/(1 + w^2),v,u) returns -(dirac(1,u)*1i)/(w^2+1) % ifourier(fourier(f(x),x,w),w,x) returns f(x) % % See also SYM/FOURIER, SYM/ILAPLACE, SYM/IZTRANS, SUBS, SYMPREF. % Copyright 2011 The MathWorks, Inc. f = transform('ifourier', 'w', 'x', 't', F, varargin{:}); end