smr_array: Summarized representation of theta arrays
In mrf2d: Markov Random Field Models for Image Analysis

Description Usage Arguments Details Value Author(s) See Also Examples

smr_array creates a vector containing only the free parameters from an array given a restriction family. exapand_array is the reverse operation, expanding a complete array from the vector of sufficient statistics.

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smr_array(theta, family)

expand_array(theta_vec, family, mrfi, C)

`theta`	A 3-dimensional array describing potentials. Slices represent interacting positions, rows represent pixel values and columns represent neighbor values. As an example: `theta[1,3,2]` has the potential for the pair of values 0,2 observed in the second relative position of `mrfi`.
`family`	The family of parameter restrictions to potentials. Families are: `'onepar'`, `'oneeach'`, `'absdif'`, `'dif'` or `'free'`. See `mrf2d-familiy`.
`theta_vec`	A `numeric` vector with the free parameters of a potential array. It's dimension depends on the restriction `family`, `C` and the number of interacting positions on `mrfi`.
`mrfi`	A `mrfi` object representing the interaction structure.
`C`	The maximum value of the field.

The order the parameters appear in the summarized vector matches the order in smr_stat().

vec_description() provides a data.frame object describing which are the relative positions and interactions associated with each element of the summarized vector in the same order.

smr_array returns a numeric vector with the free parameters of theta.

expand_array returns a three-dimensional array of potentials.

Victor Freguglia

A paper with detailed description of the package can be found at doi: 10.18637/jss.v101.i08

smr_array(theta_potts, "onepar")
smr_array(theta_potts, "oneeach")

expand_array(0.99, family = "onepar", mrfi = mrfi(1), C = 2)
expand_array(c(0.1, 0.2), family = "oneeach", mrfi = mrfi(1), C = 3)