expand_if_necessary: Expand States and Transition

In heemod: Markov Models for Health Economic Evaluations

Expand States and Transition

Description

Given an unevaluated strategy, an initial number of individual and a number of cycle to compute, returns the evaluated version of the objects and the count of individual per state per model cycle.

Usage

expand_if_necessary(
  strategy,
  parameters,
  cycles,
  init,
  method,
  expand_limit,
  inflow,
  strategy_name
)

Arguments

strategy	An uneval_strategy object.
parameters	Optional. An object generated by define_parameters().
cycles	positive integer. Number of Markov Cycles to compute.
init	numeric vector, same length as number of model states. Number of individuals in each model state at the beginning.
method	Counting method.
expand_limit	A named vector of state expansion limits.
inflow	Numeric vector, similar to init. Number of new individuals in each state per cycle.
strategy_name	Name of the strategy.

Details

init need not be integer. E.g. c(A = 1, B = 0.5, C = 0.1, ...).

Value

Expanded states, transitions, input and inflow (if they require expansion; otherwise return inputs unchanged).

Examples

param <- define_parameters(
  a = model_time + 1 * 2
)

mat <- define_transition(
  1-1/a, 1/a,
  .1,    .9
)

mod <- define_strategy(
  transition = mat,
  A = define_state(cost = 10),
  B = define_state(cost = 2)
)

heemod:::eval_strategy(
  strategy = mod,
  parameters = param,
  init = define_init(A = 10, B = 5),
  cycles = 5,
  method = "end",
  inflow = define_inflow(A = 0, B = 0),
  strategy_name = "A",
  expand_limit = c(A = 5, B = 5)
)

heemod documentation built on May 29, 2024, 8:17 a.m.