# How can I build a model to approximate the function $f(n) = 2n$?

I made the following HTML nd javascript to predict $$f(n) = 2n$$. Basically, I am trying to design my first neural network which predicts 2 multiplied by a number. I know we don't need a neural network for this, but just for a beginner, can you tell how I can make it work properly? For example, when I input 2 it gives $$89.7614166111441$$. What's wrong with my implementation?

Here's my HTML file.

<!DOCTYPE html>
<html>

<body>
<script src="l1.js" charset="utf-8"></script>
<script type="text/javascript">
//amulth(lh);

var n = 0;
var nn = 0;
var nnn = 0;
var nnnn = 0;

while (nnn < 100000000 /*0*/ ) {
nnnn = Math.round(100 * Math.random());
n = eamulth(lh1, amulth(lhlh, famulth(lh, nnnn + 0 /**parseFloat(prompt("Enter a number"))*/ , lh1lh), lhl), lh1l);
/*n=1;*/
nn = /*parseFloat(prompt(""+n))*/ 2 * nnnn - n;
lh = t(lh, nn, 0.1);
lh1 = t(lh1, nn, 0.01);
/*lh1l=t(lh1l,nn,0.01);
lhl=t(lhl,nn,0.01);*/
nnn++;
lhlh = t(lhlh, nn, 0.01);
lh1lh = t(lh1lh, nn, 0.01);

}
alert(eamulth(lh1, famulth(lh, parseFloat(prompt("Enter a number")), lhl), lh1l));
alert(eamulth(lh1, amulth(lhlh, famulth(lh, nnnn + 0 /**parseFloat(prompt("Enter a number"))*/ , lh1lh), lhl), lh1l));
</script>

</body>

</html>


Here's the Javascript file.

//l1.js
var lh = [0, 0, 0, 0, 0, 0, 0, 0, 0, 0];
var lh1 = [0, 0, 0, 0, 0, 0, 0, 0, 0, 0];
var lhl = [0, 0, 0, 0, 0, 0, 0, 0, 0, 0];
var lh1l = [0, 0, 0, 0, 0, 0, 0, 0, 0, 0];
lh = [1, 1, 1, 1, 1, 1, 1, 1, 1, 1];
lh1 = [1, 1, 1, 1, 1, 1, 1, 1, 1, 1];
lhl = [1, 1, 1, 1, 1, 1, 1, 1, 1, 1];
lh1l = [1, 1, 1, 1, 1, 1, 1, 1, 1, 1];

var lhlh = [1, 1, 1, 1, 1, 1, 1, 1, 1, 1];
var lh1lh = [1, 1, 1, 1, 1, 1, 1, 1, 1, 1];

function amulth(hh, hhh, aa) {

var ta = [];
var s = 0;

for (var i = 0; i < hh.length; i++) {
for (var j = 0; j < hhh.length; j++) {

s += hhh[j] * hh[i];
}
s += 0 + 0 + aa[i];
ta.push(s);
s = 0;
}
return ta;

}

function famulth(hh1, hhh1, aa1) {

var ta1 = [];

for (var i1 = 0; i1 < hh1.length; i1++) {
ta1.push(hh1[i1] * hhh1 + aa1[i1]);
}
return ta1;

}

function eamulth(hh2, hhh2, aa) {

var ta2 = 0;
for (var i2 = 0; i2 < hh2.length; i2++) {

ta2 += hhh2[i2] * hh2[i2] + aa[i2];

}
return ta2;
}

function t(hh3, d1, lhhhh) {
for (var il = 0; il < hh3.length; il++) {
hh3[il] = hh3[il] + d1 * lhhhh * 0.0001;
}
return hh3;
}

• Hi and welcome to this community! What is your question? You forgot to ask a question. I would like to note that if you want us to debug your source code, your question is probably off-topic here and should probably be asked on Data Science SE or Stack Overflow. – nbro Dec 13 '19 at 16:00
• After the upload all writing got messed up .I am trying to fix it. – compenthusiast Dec 13 '19 at 16:01
• wait some time. – compenthusiast Dec 13 '19 at 16:01
• well everything above the ________ line is my html file which uses the javascript code provided in the file below ________ line .Sorry for strange function and variable names . – compenthusiast Dec 13 '19 at 16:05
• Here we focus on theoretical and philosophical aspects of artificial intelligence, that's why I was suggesting you to ask your question on Data Science SE or Stack Overflow. – nbro Dec 13 '19 at 16:07