imp2state {DAKS} | R Documentation |
imp2state
transforms a set of implications (ought to be
a surmise relation) to the corresponding set of knowledge states
(the quasi ordinal knowledge space).
imp2state(imp, items)
imp |
a required object of class set
representing the set of implications, for instance obtained from a
call to iita . |
items |
a required numeric giving the number of items of the
domain taken as basis for imp . |
If the arguments imp
and items
are of required types,
imp2state
returns a matrix consisting of ones or zeros (the
quasi ordinal knowledge space), in which each row represents the
1/0-pattern of a knowledge state.
For any set of implications the returned knowledge structure is a quasi ordinal knowledge space. In case of a surmise relation this is Birkhoff's theorem. For details refer to Doignon and Falmagne (1999, Theorem 1.49).
A set of implications, an object of the class
set
, consists of 2-tuples (i, j) of
the class tuple
, where a 2-tuple
(i, j) is interpreted as `mastering item j implies
mastering item i.'
Anatol Sargin anatol.sargin@math.uni-augsburg.de, Ali Uenlue ali.uenlue@math.uni-augsburg.de
Doignon, J.-P. and Falmagne, J.-C. (1999) Knowledge Spaces. Berlin, Heidelberg, and New York: Springer-Verlag.
Sargin, A. and Uenlue, A. (2009) DAKS: An R package for data analysis in knowledge space theory. Manuscript submitted for publication. http://www.math.uni-augsburg.de/~uenlueal/
state2imp
for transformation from knowledge states to
implications. See also DAKS-package
for general
information about this package.
x <- iita(pisa, v = 1) imp2state(x$implications, ncol(pisa))