David Roundy wrote:
On Sun, Jun 12, 2005 at 08:00:02PM +0100, Keean Schupke wrote:
- Standard arithmetic operators do standard matrix operations (except "/" is unimplemented - until I write a Gaussian-elimination routine)
It would be nice to at least implement "/" for division by scalars... yes one could use ./ for that, but it's less nice.
Can be done... matrix division also not that hard...
- 'dot' operators '.*' './' do elementwise operations on matrices, and are composed into a matrix level analogue of the standard Numeric class hierachy. - Any operation involving a scalar applies that operation to each element in the matrix.
Looks nice.
- operations in Floating that have no obvious matrix equivalents are applied elementwise (sin/cos/tan)
At least sin and cos do have matrix equivalents (imag(mexp(M)), etc)...
You learn something everyday... I guess I knew this already as I know about the power series definitions of sin and cos... guess I just didn't think about it too much. Would we rather have: sin and sinm (elementwise and matrix) - same as matlab OR sine and sin (elementwise and matrix) - applies matrix form as 'normal' OR some other.
- operations in Floating that have matrix equivalents (exp) are applied elementwise for consistancy with the other functions in the Floating class.
Okay... I don't really expect to use mexp anyways (although it *is* handy in quantum mechanics, if you can store the entire hamiltonian).
Shouldn't this be an instance of Functor, and have the mmap be called fmap? I'd would lean towards making 'exp' be matrix exponentiation.
Ah... No. class Functor m where fmap :: a -> b -> m a -> m b But the type of "mmap" is mmap :: e -> e -> Matrix a i e -> Matrix a i e in other words we map values to the same type, not a different type.
I will add features as I require them, but if anyone actually wants to use it, I will consider patches and requests for features...
I don't suppose there's a chance you could set up a public darcs repository for this?
Yes ... will do.
Idea's and improvements greatly appreciated...
One thing that would really help would be a nicer show instance. As a corollary, a read instance would also be nice.
Definitely, had planned to do this. Keean.