View source: R/set_restrictions.R

set_restrictions | R Documentation |

Restrict a model's parameter space. This reduces the number of nodal types and in consequence the number of unit causal types.

set_restrictions( model, statement = NULL, join_by = "|", labels = NULL, given = NULL, keep = FALSE, update_types = TRUE, wildcard = FALSE )

`model` |
A |

`statement` |
A quoted expressions defining the restriction. If values for some parents are not specified, statements should be surrounded by parentheses, for instance |

`join_by` |
A string. The logical operator joining expanded types when |

`labels` |
A list of character vectors specifying nodal types to be kept or removed from the model. Use |

`given` |
A character vector or list of character vectors specifying nodes on which the parameter set to be restricted depends. When restricting by |

`keep` |
Logical. If 'FALSE', removes and if 'TRUE' keeps only causal types specified by |

`update_types` |
Logical. If 'TRUE' the 'causal_types' matrix gets updated after application of restrictions. |

`wildcard` |
Logical. If 'TRUE' allows for use of wildcards in restriction string. Default 'FALSE'. |

Restrictions are made to nodal types, not to unit causal types. Thus for instance in a
model `X -> M -> Y`

, one cannot apply a simple restriction so that `Y`

is nondecreasing
in `X`

, however one can restrict so that `M`

is nondecreasing in `X`

and `Y`

nondecreasing in `M`

.
To have a restriction that `Y`

be nondecreasing in `X`

would otherwise require restrictions on causal types, not nodal types,
which implies a form of undeclared confounding (i.e. that in cases in which `M`

is decreasing in `X`

, `Y`

is decreasing in `M`

).

Since restrictions are to nodal types, all parents of a node are implicitly fixed. Thus for model `make_model(`X -> Y <- W`)`

the request
`set_restrictions(`(Y[X=1] == 0)`)`

is interpreted as `set_restrictions(`(Y[X=1, W=0] == 0 | Y[X=1, W=1] == 0)`)`

.

Statements with implicitly controlled nodes should be surrounded by parentheses, as in these examples.

Note that prior probabilities are redistributed over remaining types.

An object of class `model`

. The causal types and nodal types in the model are reduced according to the stated restriction.

Other restrictions:
`restrict_by_labels()`

,
`restrict_by_query()`

# 1. Restrict parameter space using statements model <- make_model('X->Y') %>% set_restrictions(statement = c('X[] == 0')) model <- make_model('X->Y') %>% set_restrictions(non_increasing('X', 'Y')) model <- make_model('X -> Y <- W') %>% set_restrictions(c(decreasing('X', 'Y'), substitutes('X', 'W', 'Y'))) model$parameters_df model <- make_model('X-> Y <- W') %>% set_restrictions(statement = decreasing('X', 'Y')) model$parameters_df model <- make_model('X->Y') %>% set_restrictions(decreasing('X', 'Y')) model$parameters_df model <- make_model('X->Y') %>% set_restrictions(c(increasing('X', 'Y'), decreasing('X', 'Y'))) model$parameters_df # Restrict to define a model with monotonicity model <- make_model('X->Y') %>% set_restrictions(statement = c('Y[X=1] < Y[X=0]')) get_parameter_matrix(model) # Restrict to a single type in endogenous node model <- make_model('X->Y') %>% set_restrictions(statement = '(Y[X = 1] == 1)', join_by = '&', keep = TRUE) get_parameter_matrix(model) # Use of | and & # Keep node if *for some value of B* Y[A = 1] == 1 model <- make_model('A->Y<-B') %>% set_restrictions(statement = '(Y[A = 1] == 1)', join_by = '|', keep = TRUE) dim(get_parameter_matrix(model)) # Keep node if *for all values of B* Y[A = 1] == 1 model <- make_model('A->Y<-B') %>% set_restrictions(statement = '(Y[A = 1] == 1)', join_by = '&', keep = TRUE) dim(get_parameter_matrix(model)) # Restrict multiple nodes model <- make_model('X->Y<-M; X -> M' ) %>% set_restrictions(statement = c('(Y[X = 1] == 1)', '(M[X = 1] == 1)'), join_by = '&', keep = TRUE) get_parameter_matrix(model) # Restrict using statements and given: model <- make_model("X -> Y -> Z; X <-> Z") %>% set_restrictions(list(decreasing('X','Y'), decreasing('Y','Z')), given = c(NA,'X.0')) get_parameter_matrix(model) # Restrictions on levels for endogenous nodes aren't allowed ## Not run: model <- make_model('X->Y') %>% set_restrictions(statement = '(Y == 1)') ## End(Not run) # 2. Restrict parameter space Using labels: model <- make_model('X->Y') %>% set_restrictions(labels = list(X = '0', Y = '00')) # Restrictions can be with wildcards model <- make_model('X->Y') %>% set_restrictions(labels = list(Y = '?0'), wildcard = TRUE) get_parameter_matrix(model) # Deterministic model model <- make_model('S -> C -> Y <- R <- X; X -> C -> R') %>% set_restrictions(labels = list(C = '1000', R = '0001', Y = '0001'), keep = TRUE) get_parameter_matrix(model) # Restrict using labels and given: model <- make_model("X -> Y -> Z; X <-> Z") %>% set_restrictions(labels = list(X = '0', Z = '00'), given = c(NA,'X.0')) get_parameter_matrix(model)

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