Description Details Extends Fields Constructor Methods Author(s) See Also Examples

This class represents a score for causal inference from observational Gaussian
data; it is used in the causal inference function `ges`

.

The class implements an *ℓ0*-penalized Gaussian maximum
likelihood estimator. The penalization is a constant (specified by
the argument `lambda`

in the constructor) times the number of
parameters of the DAG model. By default, the constant *λ* is
chosen as *log(n)/2*, which corresponds to the BIC score.

Class `"Score"`

, directly.

All reference classes extend and inherit methods from `"envRefClass"`

.

The class `GaussL0penObsScore`

has the same fields as
`Score`

. They need not be accessed by the user.

1 2 3 4 5 6 |

`data`

Data matrix with

*n*rows and*p*columns. Each row corresponds to one observational realization.`lambda`

Penalization constant (cf. details)

`intercept`

Indicates whether an intercept is allowed in the linear structural equations, or, equivalently, if a mean different from zero is allowed for the observational distribution.

`use.cpp`

Indicates whether the calculation of the score should be done by the C++ library of the package, which speeds up calculation. This parameter should only be set to

`FALSE`

in the case of problems.

`local.score(vertex, parents, ...)`

Calculates the local score of a vertex and its parents. Since this score has no obvious interpretation, it is rather for internal use.

`global.score.int(edges, ...)`

Calculates the global score of a DAG, represented as a list of in-edges: for each vertex in the DAG, this list contains a vector of parents.

`global.score(dag, ...)`

Calculates the global score of a DAG, represented as an object of a class derived from

`ParDAG`

.`local.mle(vertex, parents, ...)`

Calculates the local MLE of a vertex and its parents. The result is a vector of parameters encoded as follows:

First element: variance of the Gaussian error term

Second element: intercept

Following elements: regression coefficients; one per parent vertex

`global.mle(dag, ...)`

Calculates the global MLE of a DAG, represented by an object of a class derived from

`ParDAG`

. The result is a list of vectors, one per vertex, each in the same format as the result vector of`local.mle`

.

Alain Hauser ([email protected])

`ges`

,
`GaussL0penIntScore`

,
`Score`

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 | ```
##################################################
## Using Gaussian Data
##################################################
## Load predefined data
data(gmG)
## Define the score object
score <- new("GaussL0penObsScore", gmG$x)
## Score of the true underlying DAG
score$global.score(as(gmG$g, "GaussParDAG"))
## Score of the DAG that has only one edge from 1 to 2
A <- matrix(0, ncol(gmG$x), ncol(gmG$x))
A[1, 2] <- 1
score$global.score(as(A, "GaussParDAG"))
## (Note: this is lower than the score of the true DAG.)
``` |

```
[1] -20026.75
[1] -25252.49
```

pcalg documentation built on June 5, 2018, 1:05 a.m.

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