sicmutils.numerical.ode — net.littleredcomputer/sicmutils 0.12.1

evolve clj

(evolve state-derivative & state-derivative-args)

evolve takes a state derivative function constructor and its arguments, and returns an integrator via make-integrator. In particular, the returned function accepts a callback function which will be invoked at intermediate grid points of the integration.

integrate-state-derivative clj

(integrate-state-derivative state-derivative
                            state-derivative-args
                            initial-state
                            t1
                            dt)

A wrapper for evolve, which is more convenient when you just want a vector of (time, state) pairs over the integration interval instead of having to deal with a callback. Integrates the supplied state derivative (and its argument package) from [0 to t1] in steps of size dt

make-integrator clj

(make-integrator state-derivative derivative-args)

make-integrator takes a state derivative function (which in this system is assumed to be a map from a structure to a structure of the same shape, as differentiating a function does not change its shape), and returns an integrator, which is a function of several arguments: the initial state, an intermediate-state observation function, the step size desired, the final time to seek, and an error tolerance. If the observe function is not nil, it will be invoked with the time as first argument and integrated state as the second, at each intermediate step.

state-advancer clj

(state-advancer state-derivative & state-derivative-args)

state-advancer takes a state derivative function constructor followed by the arguments to construct it with. The state derivative function is constructed and an integrator is produced which takes the initial state, target time, and error tolerance as arguments. The final state is returned. The state derivative is expected to map a structure to a structure of the same shape, and is required to have the time parameter as the first element.