Matrix Viewer actor does not accept RExpression matrices
2-way tables are a common way to view relationships between bivariate data. The The RExpression actor is quite good at generating these and the Matrix Viewer actor seems like a logical vehicle for displaying them. The Viewer does not display the matrix, however, probably because, as the documentation says, it "...accepts matrix tokens (e.g., [1, 2; 3, 4]...", which is not the way matrices are represented in R (though they can be in Matlab). I am way out of my depth in discussions of the way such data is stored in, and output from, the RExpression actor (or in R for that matter). But, maybe I can say that if you want folks to be able to generate high-quality output in workflows, adequate presentation of a 2-way table would be a pretty basic expectation.
#1 Updated by Dan Higgins about 14 years ago
The RExpression matrix was created solely to pass a matrix to another RExpression actor. It is NOT a Kepler/Ptolemy matrix, so the Ptolemy matrix viewer is not expected to work. Converting an R matrix to a Ptolemy matrix on output would solve this problem but would be quite inefficient if the output was just going to another RExpression actor where it would have to be converted back to the R format.
Note I am not suggesting that an R matrix display would not be useful, just that it is tied into the whole issue of format of data passed between actors.