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Could this be improved?

• To: mathgroup at smc.vnet.net
• Subject: [mg21741] Could this be improved?
• From: "Jordan Rosenthal" <jr at ece.gatech.edu>
• Date: Wed, 26 Jan 2000 03:45:40 -0500 (EST)
• Organization: Georgia Institute of Technology, Atlanta GA, USA
• Sender: owner-wri-mathgroup at wolfram.com

Hi all,

I wrote the following code which works correctly.  I was wondering, however,
if there was a way of doing the same thing that had more of a Mathematica
approach.  I am new to Mathematica and am still trying to get a grasp on how
to program effectively within the environment.

myMtx[v_] := Module[
    {nCols, nRows, vPadded, c},
    nCols = Length[v];
    nRows = 2nCols - 1;
    c = ZeroMatrix[nRows, nCols];
    vPadded = PadRight[v, nRows, 0];
    For[i = 1, i <= nCols, i++,
      c[[All, i]] = vPadded;
      vPadded = RotateRight[vPadded]
      ];
    c
    ]

For example, myMtx[{1,2,3}] takes the vector {1,2,3} and turns it into the
matrix {{1, 0, 0}, {2, 1, 0}, {3, 2, 1}, {0, 3, 2}, {0, 0, 3}} which looks
like

[ 1 0 0 ]
[ 2 1 0 ]
[ 3 2 1 ]
[ 0 3 2 ]
[ 0 0 3 ]


Thanks,

Jordan

• Follow-Ups:
  • Re: Could this be improved?
    • From: Hartmut Wolf <hwolf@debis.com>