Re: matrix

• To: mathgroup at smc.vnet.net
• Subject: [mg5530] Re: matrix
• From: "w.meeussen" <w.meeussen at solair4b.eunet.be>
• Date: Thu, 19 Dec 1996 01:02:30 -0500
• Sender: owner-wri-mathgroup at wolfram.com

```At 19:26 14-12-96 -0500, you wrote:
>Who can help me solve the following problem:
>
>Given two vectors
>v = {1/x^3,x,x,x,1/x,1/x,1/x,x^3}
>w = a{1/x^3,x,x,x,0,0,0,0}
>
>where x is real, find a unitary matrix U which takes v to w:
>U.v == w
>
>(the parameter a normalizes w so it has the same length as v).
>
>The problem here is to find a REALISTIC way to solve this in Mathematica.
>Simply setting this up using Solve etc. crunches away for ever.
>
>
>Dani
>
>
hi Dani,

sorry if this is stupid, but could it be as simple as:

u=Table[If[i>4,0,1]If[i==j,1,0],{i,8},{j,8}]

{{1, 0, 0, 0, 0, 0, 0, 0}, {0, 1, 0, 0, 0, 0, 0, 0}, {0, 0, 1, 0, 0, 0, 0,
0}, {0, 0, 0, 1, 0, 0, 0, 0},
{0, 0, 0, 0, 0, 0, 0, 0}, {0, 0, 0, 0, 0, 0, 0, 0}, {0, 0, 0, 0, 0, 0, 0,
0}, {0, 0, 0, 0, 0, 0, 0, 0}}

(a u) . v //InputForm

{a/x^3, a*x, a*x, a*x, 0, 0, 0, 0}

just a Identity matrix with the last 4 diagonal elements set to zero?

Wouter.
Dr. Wouter L. J. MEEUSSEN
w.meeussen at solair4b.eunet.be

```

• Prev by Date: Help
• Next by Date: Re: How to get rid of the outer {}?
• Previous by thread: Re: Help
• Next by thread: Japanese Tester Position