matrix expansion

[Anon]

hello all...
now i build an intranet application in a company that have electrical engineering background. in some application i have to generate matrix that call Hadamard Matrix, note: digital case. The algoritm is preaty easy, but i never use multi dimentional matrix. the matrix is like this:

Hn/2  Hn/2    

Hn=
Hn/2 -Hn/2

example
1 1
H[2]=
1 -1

  1   1   1   1

H[4]= 1 -1 1 -1
1 1 -1 -1
1 -1 -1 1

H[8] is H[4] H[4]
H[4] -H[4]
according to formula above..
i think this use 2 dimension array

anybody solve this problem, urgent please.......

[majik-sheff]

I'm sorry, could you please explain that again?

[Anon]

// Illustrative only. Testing/fixing and
// bulletproofing is left as an exercise for the implementor.

function HadamardStep($matrix)
{
$nextstep=array();
$n=sizeof($matrix);
for($i=0;$i<$n;++$i)
{
for($j=0;$j<$n;++$j)
{
$newmatrix[$i][$j] = $newmatrix[$i][2$j] = $newmatrix[2$i][$j]=$matrix[$i][$j];
$newmatrix[2$i][2$j] = -$matrix[$i][$j];
}
}
return $newmatrix;
}

function HadamardMatrix($n)
{
$h=array(1);
if($n==1) return $h;
for($i=1;$i<$n;++$i){
$h=HadamardStep($h);
}
return $h;
}

[Anon]

function HadamardStep($matrix)
{
$newmatrix=array();
$n=sizeof($matrix);
for($i=0;$i<$n;++$i)
{
for($j=0;$j<$n;++$j)
{
$newmatrix[$i][$j] = $newmatrix[$i][2$j] = $newmatrix[2$i][$j] = $matrix[$i][$j];
$newmatrix[2$i][2$j] = -$matrix[$i][$j];
}
}
return $newmatrix;
}