Re: random matrix initialisation...
- To: mathgroup at smc.vnet.net
- Subject: [mg37610] Re: [mg37576] random matrix initialisation...
- From: Tomas Garza <tgarza01 at prodigy.net.mx>
- Date: Wed, 6 Nov 2002 06:54:36 -0500 (EST)
- References: <200211051001.FAA14245@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
Try this: In[1]:= << "DiscreteMath`Combinatorica`" In[2]:= bigX[m_, n_] := Module[ {st = Join[Table[1, {n}], Table[0, {m^2 - n}]]}, Partition[st[[RandomPermutation[m^2]]], m]] In[3]:= bigX[4, 3] Out[3]= {{0, 0, 0, 0}, {0, 0, 0, 1}, {0, 0, 0, 1}, {0, 1, 0, 0}} In[4]:= bigX[4, 3] Out[4]= {{0, 0, 0, 0}, {0, 1, 0, 0}, {0, 0, 1, 0}, {0, 0, 0, 1}} Tomas Garza Mexico City ----- Original Message ----- From: "Manuel Marques-Pita" <manuxu at mac.com> To: mathgroup at smc.vnet.net Subject: [mg37610] [mg37576] random matrix initialisation... > > hello, > > i have a question regarding matrices. searched on the web and forums > but maybe due to using wrong keywords i am not finding an answer... > > i need a way or function X to initialise matrices in mathematica such > that each time i call X i get a matrix with a predetermined number of > elements initialised as "1" and the rest as "0" > > examples > > X(4,3) > > {{0,0,0,0}, {0,0,1,0}, {0,0,0,1}, {1,0,0,0}} > > again X(4,3) > > {{1,1,0,0}, {0,0,0,0}, {0,0,0,0}, {0,1,0,0}} > > etc.. (first argument means that the matrix is 4x4 and second means > that there should be 3 "1's" present in the matrix > > any help, pointers, etc will be appreciated! > > thanks a lot > > m > > -- > >
- References:
- random matrix initialisation...
- From: Manuel Marques-Pita <manuxu@mac.com>
- random matrix initialisation...