bga and other functions in made4 call this function and it is
generally not necessary to call array2ade4 this directly.array2ade4 calls getdata, and will accept a matrix, data.frame,
ExpressionSet or marrayRaw-class format.
It will also transpose data or add a integer to generate a positive data matrix.
If the input data contains missing values (NA), these must first be removed or imputed (see the R libraries impute() or pamr()).