sdepy.integrator.begin

integrator.begin()

Set initial conditions.

Given the time points sw[0], ..., sw[depth - 2], should define and store in the working space the corresponding initial values xw[0], ..., xw[depth - 2]. Note that when begin gets called, sw[depth - 1] and xw[depth - 1] are undefined and will be respectively set, and computed, at the first iteration.

Notes

It is called once for each backwards and forwards simulation, after memory allocation and before starting the iteration along the time points in steps_tt.

Outline of expected code for depth=2:

# access itervars
iv = self.itervars
sw, xw = iv['sw'], iv['xw']

# this is the initial time, taken from the
# simulation timeline
t0 = sw[0]
assert t0 == iv['steps_tt'][0] == iv['tt'][0]

# store the initial condition
xw[0][...] = 1.

Must be provided by subclasses.