function F = fisher(p1, p2, p3, p4, p5, p6, p7, p8)% fisher -- compute the fisher information matrix%%  Usage%    F = fisher(N, sigma, A, d, c, t, omega, phi)%    F = fisher(t, omega, c, d)%%  Inputs%    N      number of data points%    sigma  std of the CWGN%    A      amplitude%    d      duration%    c      chirp rate%    t      time%    omega  frequency%    phi    constant phase%%  Outputs%    F      fisher information matrix, either 7x7 or 4x4 depending %           on the number of input parameters% Copyright (C) -- see DiscreteTFDs/Copyrightif (nargin==8)  N = p1;  sigma = p2;  A = p3;  d = p4;  c = p5;  t = p6;  w = p7;  phi = p8;  F = zeros(7,7);  F(1,1) = N/A^2/sigma^2;  F(2,2) = 1/A^2;  F(3,3) = 1/2/d^2;  F(4,4) = 3*d^4/4;  F(5,5) = 1/4/d^2 + c^2*d^2 + w^2;  F(6,6) = d^2;  F(7,7) = 1;  F(4,5) = -w*d^2/2;  F(5,4) = F(4,5);  F(4,7) = d^2/2;  F(7,4) = F(4,7);  F(5,6) = -c*d^2;  F(6,5) = F(5,6);  F(5,7) = -w;  F(7,5) = -w;  F = F*A^2/sigma^2;elseif (nargin==4)  t = p1;  w = p2;  c = p3;  d = p4;  F = zeros(10,1);  F(1) = 1/4/d^2 + c^2*d^2 + w^2;  F(2) = d^2;  F(3) = 3*d^4/4;  F(4) = 1/2/d^2;  F(5) = -c*d^2;  F(6) = -w*d^2/2;  F(7) = 0;  F(8) = 0;  F(9) = 0;  F(10) = 0;else  error('4 or 8 input parameters allowed')end