egttools.numerical.numerical_.calculate_expected_indicator

calculate_expected_indicator()

Calculate E[f] = sum_s sd(s) * sum_g P(g|s) * f(g) for an arbitrary indicator f.

The callable indicator receives a list of ints representing the count of each strategy in the sampled group (length nb_strategies, sums to group_size) and must return a float.

Parameters:

  • pop_size (int) – Total number of individuals in the population.

  • group_size (int) – Number of individuals sampled per group interaction.

  • nb_strategies (int) – Number of strategies available in the population.

  • stationary_distribution (scipy.sparse.csr_matrix) – Sparse matrix representing the stationary distribution over population states.

  • indicator (callable) – Function with signature f(group_config: list[int]) -> float.

Returns:

Expected value of the indicator.

Return type:

float

Examples

>>> # Expected group success for CRD: cooperators are strategy 0, threshold = 3
>>> eta_G = calculate_expected_indicator(
...     pop_size, group_size, nb_strategies, sd,
...     lambda g: float(g[0] >= 3)
... )