TITLE Finite Difference Oscillator, Sweeps constant
:  National Biomedical Simulation Resource, 3-21-91
:  Reference - Glass and Mackey, From Clocks to Chaos, Princeton
:    University Press, 1988, Chapter 2
:  Default output - bifurcation diagram
: $Header: /usr/nbsr/scop/Testing/RCS/finidiff.mod,v 11.0 90/11/20 15:13:12 nfh Exp $

PARAMETER

{
  x0 =  .8
  delta_a = .1
}

INDEPENDENT
{
  t FROM 0 TO 10000 WITH 10000
}

PLOT x VS a

ASSIGNED
{
  a FROM 0 TO 5
  tsweep
}

STATE
{
  x FROM 0 TO 1.5
}

INITIAL
{
  tsweep = t
  a = 0
}

DISCRETE eqns
{
  x = a * x@1 * (1 - x@1)
  IF (x < 0) { x = 0 }          : Protect from negative values
}

BREAKPOINT

{
  tsweep = tsweep + 1
  IF (tsweep >= 200)
  {
    tsweep = tsweep - 200
    x = x0
    a = a + delta_a
  }

  SOLVE eqns
}