Help with a Fold/Outer one-liner
- To: mathgroup at smc.vnet.net
- Subject: [mg28220] Help with a Fold/Outer one-liner
- From: "Emilio Martin-Serrano Sobrino" <emilio.martin at sema.es>
- Date: Thu, 5 Apr 2001 03:00:33 -0400 (EDT)
- Sender: owner-wri-mathgroup at wolfram.com
Hi math groupers: Could anyone give me a hand with this? Let {m[1],m[2], m[3],m[4]} be a list of tensors over N^4 . I want to apply the following function to the previous list: With[{vars = {x1,x2,x3,x4}}, Fold[Outer[D, #, vars]&, m1,{m2,m3,m4}]] (*let us consider {x1,x2,x3,x4} as the actual dimension names } *). In fact the length of the list and the dimensions should not matter, I put "4" to make things clearer. And I did this: With[{vars =(*Extract de list of the dimensions names to differentiate*)}, Fold[Outer[D, #, vars]&, First[List@@#],Drop[List@@#,1]]]&/@ Sequence[m1,m2,m3,m4]; But it does not work. My main problem is with how to extract the dimension names (or the length) Any help? Regards Emilio Martin-Serrano ------------------------------------------------------------------ This email is confidential and intended solely for the use of the individual to whom it is addressed. Any views or opinions presented are solely those of the author and do not necessarily represent those of Sema Group. If you are not the intended recipient, be advised that you have received this email in error and that any use, dissemination, forwarding, printing, or copying of this email is strictly prohibited. ------------------------------------------------------------------