% This function implements the Jacobian matrix for the
% equations of motion given by stiffeq.m. Borrowing
% from Octave's help page for LSODE, the form of the
% Jacobian should be:
%
%                       | df_1  df_1       df_1 |
%                       | ----  ----  ...  ---- |
%                       | dq_1  dq_2       dq_N |
%                       |                       |
%                       | df_2  df_2       df_2 |
%                       | ----  ----  ...  ---- |
%                df_i   | dq_1  dq_2       dq_N |
%     jacobian = ---- = |                       |
%                dq_j   |  .    .     .    .    |
%                       |  .    .      .   .    |
%                       |  .    .       .  .    |
%                       |                       |
%                       | df_N  df_N       df_N |
%                       | ----  ----  ...  ---- |
%                       | dq_1  dq_2       dq_N |
%
%
% CCK 2009-Mar-02
function dfdq = stiffeq_jacobian(q,t)

dfdq(1,1:2) = [-1001, 1000];
dfdq(2,1:2) = [1000, -1001];

