Henning Thielemann wrote:
I'm uncertain about how who want to put the different kinds of multiplication into one method, even with multi-parameter type classes. You need instances
(*) :: Matrix -> Matrix -> Matrix (*) :: RowVector -> Matrix -> RowVector (*) :: Matrix -> ColumnVector -> ColumnVector (*) :: RowVector -> ColumnVector -> Scalar (*) :: ColumnVector -> RowVector -> Matrix (*) :: Scalar -> RowVector -> RowVector (*) :: RowVector -> Scalar -> RowVector (*) :: Scalar -> ColumnVector -> ColumnVector (*) :: ColumnVector -> Scalar -> ColumnVector
but you have to make sure that it is not possible to write an expression which needs (*) :: Matrix -> RowVector -> RowVector
Further you need transpose :: RowVector -> ColumnVector transpose :: ColumnVector -> RowVector transpose :: Matrix -> Matrix and you must forbid, say transpose :: RowVector -> RowVector
Of course if they are all of type Matrix this problem disappears. What is the difference between a 1xN matrix and a vector? Please explain... Keean.