Mathematica 9 is now available
Services & Resources / Wolfram Forums
-----
 /
MathGroup Archive
2000
*January
*February
*March
*April
*May
*June
*July
*August
*September
*October
*November
*December
*Archive Index
*Ask about this page
*Print this page
*Give us feedback
*Sign up for the Wolfram Insider

MathGroup Archive 2000

[Date Index] [Thread Index] [Author Index]

Search the Archive

Re: Could this be improved?

  • To: mathgroup at smc.vnet.net
  • Subject: [mg21757] Re: Could this be improved?
  • From: "Allan Hayes" <hay at haystack.demon.co.uk>
  • Date: Thu, 27 Jan 2000 22:56:38 -0500 (EST)
  • References: <86mdpv$2f3@smc.vnet.net>
  • Sender: owner-wri-mathgroup at wolfram.com

Jordan:

myMtx[v_] :=
  Reverse[Partition[PadLeft[Reverse[#], 3#2 - 2, {0}, #2 - 1], #2, 1]] &[v,
    Length[v]]

myMtx[{1, 2, 3}]

        {{1, 0, 0}, {2, 1, 0}, {3, 2, 1}, {0, 3, 2}, {0, 0, 3}}


--
Allan
---------------------
Allan Hayes
Mathematica Training and Consulting
Leicester UK
www.haystack.demon.co.uk
hay at haystack.demon.co.uk
Voice: +44 (0)116 271 4198
Fax: +44 (0)870 164 0565


"Jordan Rosenthal" <jr at ece.gatech.edu> wrote in message
news:86mdpv$2f3 at smc.vnet.net...
> 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
>
>
>
>
>



  • Prev by Date: Re: Could this be improved?
  • Next by Date: Re: Could this be improved?
  • Previous by thread: Re: Could this be improved?
  • Next by thread: Re: Could this be improved?