bucky.util.ode_constraints#

Constrant decorators for the RHS funcs used in the ODE solvers.

Module Contents#

Functions#

constrain_y_range(constraints)

Decorator wrapping a function to be passed to an ODE solver which constrains the solution space.
bucky.util.ode_constraints.constrain_y_range(constraints)[source]#

Decorator wrapping a function to be passed to an ODE solver which constrains the solution space.

Examples

@constrain([0, 1])
def f(t, y):
  dy_dt = # your ODE
  return dy_dt

solver = scipy.integrate.odeint(f, y0)  # use any solver you like!
solution = solver.solve()

If solution goes below 0 or above 1, the function f will ignore values of dy_dt which would make it more extreme, and treat the previous solution as if it were at 0 or 1.

Parameters:

constraints (set) – Sequence of (low, high) constraints - use None for unconstrained.

Notes

This constrains the dependent variable from going any further past the constraints. The ODE will still treat it as if it were at the value of the constraint, and with a small step size any problems should be minimal, but you may still have slightly out-of-range numbers in your solution.