In jordagaman/zddr: A zero-suppressed binary decision diagram implementation for R

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zddr

The goal of zddr is to enable definition, manipulation, and solving of fault tree problems using an implementation of zero-suppressed binary decision diagram algorithms in R.

Installation

Install the development version from GitHub with:

# install.packages("devtools")
devtools::install_github("jordagaman/zddr")

IMPORTANT: The functions from this package will not work properly if invoked without a library(zddr) call first. For example, calling zddr::zdd(1L) should not work. Sorry.

Example

This is a simple cutset.

library(zddr)
zdd(1) * zdd(2) * zdd(3)

You can create the same cutset above with a simpler call:

zdd_and(1, 2, 3)

Multiple cutsets look like this:

zdd_and(1, 2, 3) | zdd_and(4, 5) | zdd(6)

The real magic is ensuring that when you add a new cutset, you check if either that one or the existing ones are nonminimal. For example, {1,2,3} is nonminimal to {1}. Check this out:

zdd_and(1, 2, 3) | zdd_and(4, 5) | zdd(6) | zdd(1)

Longer-term vision

This package is in a developmental state. The ultimate dream is to simplify the user interface using the increasingly robust as_zdd() function.

The most basic use of as_zdd() accepts numeric and integer inputs.

as_zdd(10)
as_zdd(10L)

The function also assumes that vectors are meant to represent a cutset.

as_zdd( c(1,2,3) )

And lists are meant to represent a collection of cutsets.

as_zdd( list(1,2,3) )

One can combine the two to produce a ZDD representation of cutsets. The final example from the last section is reproduced here using only base R types and the as_zdd() function.

lst <- list(
  c(1,2,3),
  c(4,5),
  6,
  1
)
as_zdd(lst)

There are two effects to the above. First, it enables a complete round trip between base R cutsets and ZDDs.

z <- as_zdd(lst)
cutsets(z)
cutsets( as_zdd(cutsets(z)) )

Second, it enables quick generation and then manipulation of ZDDs without having to know too much about the internals of the zddr implementation.

z * list(1, c(2,3), 4)

jordagaman/zddr documentation built on June 29, 2021, 4:23 a.m.