(* Copyright (C) 2004-2009 Toby Cubitt This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. *) BeginPackage["Partial`","LinearAlgebra`MatrixManipulation`"] PartialTranspose::usage = "PartialTranspose[p,a,b,sys] gives the partial transpose with respect to system sys = (1 or 2) of a density matrix p with subsystems of dimensions a and b. Author: Toby Cubitt" PartialTrace::usage = "PartialTrace[p,a,b,sys] gives the partial trace with respect to system sys (1 or 2) of a density matrix p with subsystems of dimentions a and b. Author: Toby Cubitt" Begin["`Private`"] PartialTranspose[p_,a_,b_,sys_]:=Module[{s}, s=Partition[p,{b,b}]; s=Transpose[s, If[sys==1,{2,1,3,4},{1,2,4,3}] ]; s=BlockMatrix[s] ] PartialTrace[p_,a_,b_,sys_]:=Module[{s}, s=Partition[p,{b,b}]; If[sys==2,s=Transpose[s,{3,4,1,2}]]; s=Tr[s, Plus, 2] ] End[ ] EndPackage[ ]