Packing Data

DESCRIPTION:

Packing any object into an external cache.

This function requires the bigdata library section to be loaded.

USAGE:

bd.pack.object(x)
bd.unpack.object(x)

REQUIRED ARGUMENTS:

x
for bd.pack.object this can be any object. For bd.unpack.object this must be a bdPackedObject object.

VALUE:

bd.pack.object returns a bdPackedObject object, which contains a reference to an external cache holding the data. bd.unpack.object returns the unpacked data object.

DETAILS:

These functions can be used to store an arbitrary data object into an external cache, and then unpack it to retrieve the original data. The advantage of doing this is that even if the data object is quite large, the resulting bdPackedObject object is fairly small. For example, one could create a list containing thousands of packed model objects, even if a single list containing all of the unpacked objects would be too large to fit in memory.

EXAMPLES:

temp <- bd.pack.object(fuel.frame)
all.equal(fuel.frame, bd.unpack.object(temp))  # The same
object.size(fuel.frame)
object.size(temp)
# Bit smaller; though the real benefit is when working with
# much larger objects.