       Re: enquiry

• To: mathgroup at smc.vnet.net
• Subject: [mg89217] Re: enquiry
• From: dh <dh at metrohm.ch>
• Date: Thu, 29 May 2008 07:06:40 -0400 (EDT)
• References: <g1j6da\$qlu\$1@smc.vnet.net>

Hi Bico,

do not use funny names like y*, this only gives you troubles.

To solve your problem, first define a function of m and n that

calculates the matrix element: fun[m,n]. Then create the matrix. If your

indices start with 1 you can use Array, e.g.:

Array[fun,{2,3}]

There are other forms of Array for more complicated cases. But in this

case it may be easier to use Table:

Table[fun[m,n],{m,3,5},{n,2,3}]

hope this helps, Daniel

abubaker alshafee wrote:

> Hi All

>

>   I am tryin to build a Matrix

>    Vmn =  Array[v, {m, n}]  with V equal to

>

> V = (-(y*  N[BesselK[13 I, 2 Pi n y*]]

>         Exp[(13 Pi)/2]] Exp[2 Pi I n (((j - 1/2)/2)

>          Q)] Exp[-2 Pi I m (((j - 1/2)/2) Q)]))

>     (1/(2 Q)) + KroneckerDelta[m, n]

>     (Sqrt[y] N[BesselK[13 I, 2 Pi m y]

>        Exp[(13 Pi)/2]])

>

>   I used the following but I faild to get the correct matrix or array,

> I got a reapeted answers , I also need to generate a loop to build the Array of V elements Any one can help with that,

>   here the loops i wrote but it is not working

>

>   MY = 10;

> For[m = 2, m <= MY, m++,

>  Q = 11;

>  b = {};

>  y = 0.3;

>    y* = 0.3;

>  For[n = 2, n <= MY, n++,

>     For[j = 1, j <= Q, j = j + 1,

>         v = (Sqrt[y]*

>          N[BesselK[13 I,2 Pi n y*]

>          Exp[13 Pi/2)]

>          Exp[2 Pi I n ((j - 1/2) Q/2)]

>         Exp[2 Pi I m ((j - 1/2) Q/2)];

>        v = KroneckerDelta[m, n] (Sqrt[y]

>          N[BesselK[13 I, 2 Pi m y]

>            E^((13 Pi)/2), 50]) -

>        v/(2 Q);

> AppendTo[b, v];

>

>     gg = Array[v, {m, n}]]]

> Print[gg]

>

>

>

>

>   Regards

> Bico

--

Daniel Huber

Metrohm Ltd.

Oberdorfstr. 68

CH-9100 Herisau

Tel. +41 71 353 8585, Fax +41 71 353 8907

E-Mail:<mailto:dh at metrohm.com>

Internet:<http://www.metrohm.com>

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