MatrixInsert
- To: mathgroup at yoda.physics.unc.edu
- Subject: MatrixInsert
- From: HAY at leicester.ac.uk
- Date: Sat, 23 OCT 93 01:19:54 BST
- Mailer: Janet_Mailshr V3.4 (23-May-1989)
>> How can I assign a matrix to a part of another matrix? Mark Fisher's fast one-liner solution inspired a search. Here is another one - about twice as fast. MatrixInsert[A_, B_, {r_, c_}] := Block[{rB,r2,c2}, rB = Length[B]; {r2,c2} = {r,c} + Dimensions[A] -1; Join[ Take[B,r-1], MapThread[ Join[Take[#1,c-1],#2,Drop[#1,c2]]&, {Take[B,{r,r2}],A} ], Take[B, r2-rB] ] ] Allan Hayes hay at leicester.ac.uk