%% l2f1
%

%%
function [f info] = l2f1(p,tl,f0)
  % created at 2010/03/04 by Bas Kooijman, modified 2010/03/18
  
  %% Syntax 
  % [f info] = <../l2f1.m *l2f1*> (p,tl,f0)
  
  %% Description
  % Calculates f before scaled age t and scaled length l
  %
  % Input
  %
  % * p  : 4-vector with g, k, lT, v_Hb
  % * tl : 2-vector with scaled age t = a * k_M and scaled length l = L/ L_m
  % * f0 : initial estimate for scaled functional response f 
  %
  % Output
  %
  % * f : scaled funct. response up till the moment the organism reaches scaled age t and scaled length l
  % * info : scalar for 1 for success, 0 otherwise
  
  %% Example of use
  % l2f1([1;1;0;1e-3], [4, .3])

  global g k vHb lT l t

  % unpack parameters p
  g    = p(1); k    = p(2); lT   = p(3); vHb = p(4); 

  % unpack data tl
  t  = tl(1); l = tl(2);

  if exist('f0','var') == 0 % get initial estimate for f
    f0 = lT + l/ (1 - exp(-t/ 3/ (1 + 1/ g)));
  end

  [f , flag, info] = fzero('fnl2f1', f0);
  %[f info] = nmregr('fnl2f1',f0,[0 0]);