NYCPHP Meetup

[nycphp-talk] 2D array

Tracy tech_learner at yahoo.com
Wed Mar 26 07:30:44 EST 2003


Thz.
it works now but only thing is the values are "all" the same. 
Tracy
 Carlos Hoyos <cahoyos at us.ibm.com> wrote:




Multi dimensional arrays work ok in php:

instead of
> $hiddenW = array ($i => array ($n => frandom(-0.1, 0.15)));

you can use,
$hiddenW[$i][$n] = frandom(-0.1, 0.15);

The first part of code generates 2 matrices with random values. The second
one
calculates in $hiddenN the matrix product of hiddenW and inputA, and
applies the
calculates the sigmoid transform on that product (stored in hiddenA).
(for anybody remembering lineal algebra, this is just a matrix
multiplication)


You should get a numImput-fold performance improve by rewriting this:

for ($i=1; $i<=numhidden; $i++) {
$sum2=0;
for ($j=1; $j<=numInput; $j++) {
// store in temp variable $sum2 the vector product (dot product)
// of vectors $hiddenW[$i] and $inputA
$sum2 += $hiddenW[$i][$j] * $inputA[$j];
}
$hiddenN[$i]=$sum2;
$hiddenA[$i]=sigmoid($sum2);
}



Carlos




Tracy 

oo.com> cc: 
Subject: [nycphp-talk] 2D array 
03/25/2003 01:08 
AM 
Please respond to 
talk 






Hi,
below are few lines from a PASCAL code

PROCEDURE init;
VAR i, n:integer;
BEGIN
FOR i:=1 TO numhidden DO
BEGIN
hiddenA[i]:=frandom(0.005, 0.2);
FOR n:=1 TO numInput DO
hiddenW[i, n]:=frandom(-0.1, 0.15);
END;
FOR i:=1 TO numOutput DO
BEGIN
FOR n:=1 TO numhidden DO
outputW[i, n]:=frandom(-0.1, 0.15);
END;
END; { init }

the problem is i know nothing about PASCAL and there isint an elaborate
example on how to create a two-dimensional array. i am stuck at the line
hiddenW[i, n]:=frandom(-0.1, 0.15);

here's my version :
function init() {
for ($i=1; $i<=numhidden; $i++) {
$hiddenA[$i]=frandom(0.005, 0.2);
for ($n=1; $n<=numInput; $n++) {
$hiddenW = array ($i => array ($n => frandom(-0.1, 0.15)));
print("
");
   print_r($hiddenW);
   print("
");
}
}
print("
");
 print_r($hiddenA);
 print("
");
print_r($hiddenW);
for ($i=1; $i<=$numOutput; $i++) {
for ($n=1; $n<=numhidden; $n++) {
//$outputW[$i, $n]=frandom(-0.1, 0.15);
}
}
} // { init }
it seems to dump values... i am unsure if its right.
i need the values elsewhere...
for ($i=1; $i<=numhidden; $i++) {
$sum2=0;
for ($j=1; $j<=numInput; $j++) {
$sum2=$sum2 + $hiddenW[$i, $j] * $inputA[$j]; //at this point i am
totally blank
echo $sum2;
$hiddenN[$i]=$sum2;
$hiddenA[$i]=sigmoid($sum2);
}
}
has someone done this sort of programming before. there sure must be a
better way to code this procedure out. plz help
Thz
Tracy


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      working together is success !!!
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