fitfvbm {BoltzMM} R Documentation

## Maximum pseudolikelihood estimation of a fully-visible Boltzmann machine.

### Description

Estimates the bias vector and interaction matrix of a fully-visible Boltzmann machine via maximum pseudolikelihood estimation using an MM algorithm.

### Usage

```fitfvbm(data, bvec, Mmat, delta_crit = 0.001, max_it = 1000L)
```

### Arguments

 `data` An N by n matrix, where each of the N rows contains a length n string of spin variables (i.e. each element is -1 or 1). `bvec` Initial estimate for a vector of length n containing real valued bias parameters. `Mmat` Initial estimate for a symmetric n by n matrix, with zeros along the diagonal, containing the interaction parameters. `delta_crit` Real threshold value for the convergence criterion, based on the relative change in the Euclidean distance of parameter estimates from consecutive iterations. `max_it` Integer value indicating the maximum number of iterations that the algorithm is to run for.

### Value

A list containing 4 objects: the final log-pseudolikelihood value `pll`, a vector containing the estimate of the bias parameters `bvec`, a matrix containing the estimate of the interaction parameters `Mmat`, and the number of algorithm iterations `itt`.

### Author(s)

Andrew T. Jones and Hien D. Nguyen

### References

H.D. Nguyen and I.A. Wood (2016), A block successive lower-bound maximization algorithm for the maximum pseudolikelihood estimation of fully visible Boltzmann machines, Neural Computation, vol 28, pp. 485-492

### Examples

```# Generate num=1000 random strings of n=3 binary spin variables under bvec and Mmat.
num <- 1000
bvec <- c(0,0.5,0.25)
Mmat <- matrix(0.1,3,3) - diag(0.1,3,3)
data <- rfvbm(num,bvec,Mmat)
# Fit a fully visible Boltzmann machine to data, starting from parameters bvec and Mmat.
fitfvbm(data,bvec,Mmat)
```

[Package BoltzMM version 0.1.4 Index]