# Robertson-style stiff IVP using a deliberately multi-level where graph.
task
schema_version: 1
solver: IVP
method: BDF

equations
arg: t
unknowns: y1, y2, y3
rhs: -forward + backward, forward - backward - decay, decay
parameters: k1, k2, k3
parameter_values: 0.04, 1.0e4, 3.0e7

where
forward: k1*y1
backward: k2*y2*y3
decay: k3*y2*y2

initial_conditions
t0: 0.0
t_end: 1.0
y0: [1.0, 0.0, 0.0]

solver_options
rtol: 1e-6
atol: 1e-10
max_step: 0.05

continuation
parameters: k1, k3
k1_values: 0.02, 0.04
k3_values: 1.5e7, 3.0e7
mode: fresh
restart_policy: restart_with_state
monotonic: allow
y0_values: [1.0, 0.0, 0.0]
