R: Interface for NMF Seeding Methods

seed {NMF} | R Documentation

## Interface for NMF Seeding Methods

### Description

The function `seed` provides a single interface for calling all seeding methods used to initialise NMF computations. These methods at least set the basis and coefficient matrices of the initial `object` to valid nonnegative matrices. They will be used as a starting point by any NMF algorithm that accept initialisation.

IMPORTANT: this interface is still considered experimental and is subject to changes in future release.

### Usage

      seed(x, model, method, ...)

      ## S4 method for signature 'matrix,NMF,NMFSeed'
    seed(x, model, method,
        rng, ...)

      ## S4 method for signature 'ANY,ANY,function'
    seed(x, model, method, name,
        ...)

### Arguments

`x` | target matrix one wants to approximate with NMF
`model` | specification of the NMF model, e.g., the factorization rank.
`method` | specification of a seeding method. See each method for details on the supported formats.
`...` | extra to allow extensions and passed down to the actual seeding method.
`rng` | rng setting to use. If not missing the RNG settings are set and restored on exit using `setRNG`. All arguments in `...` are passed to teh seeding strategy.
`name` | optional name of the seeding method for custom seeding strategies.

### Value

an `NMFfit` object.

### Methods

seed

  `signature(x = "matrix", model = "NMF", method = "NMFSeed")`: This is the workhorse method that seeds an NMF model object using a given seeding strategy defined by an `NMFSeed` object, to fit a given target matrix.

seed

  `signature(x = "ANY", model = "ANY", method = "function")`: Seeds an NMF model using a custom seeding strategy, defined by a function.

  `method` must have signature `(x='NMFfit', y='matrix', ...)`, where `x` is the unseeded NMF model and `y` is the target matrix to fit. It must return an `NMF` object, that contains the seeded NMF model.

seed

  `signature(x = "ANY", model = "ANY", method = "missing")`: Seeds the model with the default seeding method given by `nmf.getOption('default.seed')`

seed

  `signature(x = "ANY", model = "ANY", method = "NULL")`: Use NMF method `'none'`.

seed

  `signature(x = "ANY", model = "ANY", method = "numeric")`: Use `method` to set the RNG with `setRNG` and use method “random” to seed the NMF model.

  Note that in this case the RNG settings are not restored. This is due to some internal technical reasons, and might change in future releases.

seed

  `signature(x = "ANY", model = "ANY", method = "character")`: Use the registered seeding method whose access key is `method`.

seed

  `signature(x = "ANY", model = "list", method = "NMFSeed")`: Seed a model using the elements in `model` to instantiate it with `nmfModel`.

seed

  `signature(x = "ANY", model = "numeric", method = "NMFSeed")`: Seeds a standard NMF model (i.e. of class `NMFstd`) of rank `model`.

[Package NMF version 0.20.6 Index]