Re: how to build pattern for a square matrix of reals?
- To: mathgroup at smc.vnet.net
- Subject: [mg98430] Re: how to build pattern for a square matrix of reals?
- From: Bill Rowe <readnews at sbcglobal.net>
- Date: Thu, 9 Apr 2009 05:58:12 -0400 (EDT)
On 4/8/09 at 5:03 AM, sagrailo at gmail.com wrote: >As in subject: how to build a pattern that will specify that given >argument of a function has to be square matrix of reals? Tried with >following for "square matrix" part: >f[x_?MatrixQ[#] && Dimensions[#][] == Dimensions[#][] >&] := ... but it doesn't seem to be working... You don't need the [#] after MatrixQ. Probably the simplest way to achieve the behavior you want is to specify a condition after the body of the function. For example, f[x_?MatrixQ] := Tr[x] /; SameQ @@ Dimensions[x] will compute the trace of any square matrix and be unevaluated for any argument other than a square matrix.