Error when using a matrix in cumNormStatFast()

[kivanvan]

I got an error when passing a matrix to cumNormStatFast() in cumNormMat(). It says

Error in if (class(obj) == "MRexperiment") { :
the condition has length > 1

I think it's because there are two class outputs for a matrix object: matrix and array. I couldn't find a way to make a matrix only a matrix but not an array. One possible solution I found is to use inherits(obj, "MRexperiment") in if(), which tests on only the first output from class(), but I am not sure whether that works for MRexperiment objects as well.

Is there a way to fix this error? Thanks in advance!