[SOLVED] Coordinates from ID

[Millar]

Hello.

 

I have been racking my brain, but can't think up a function to do this.

 

I want to make a function to convert and ID into a coordinate.

 

E.g.

 

1 = 1,1

2 = 2,1

3 = 1,2

4 = 2,2

5 = 3,1

6 = 3,2

7 = 1,3

8 = 2,3

9 = 3,3

10 = 4,1

11 = 4,2

12 = 4,3

13 = 1,4

14 = 2,4

15 = 3,4

16 = 4,4

 

I realise that this most probably would be based on square roots.

 

e.g 16 = 4,4 and 4 is the square root of 16. But I can't think of a way to find it for non square number ID's.

 

Thanks in advanced,

Millar.

[AndyB]

Please try that again. The example listing you give is likely to confuse people.

 

7=1,3 and 10=4,1 ????

[Orio]

This is an example for 5x5 table, where horizontal is X and vectorial is Y. So for an example 10 = (4,1) and 9 = (3,3).

1	2	5	10
3	4	6	11
7	8	9	12
13	14	15	16

 

I tried to solve this problem with no success...

I found out that the X values of coordinates and the Y values of the coordinates (each coordinate is (X,Y) of course) have a rather similar pattern, but I couldn't find out how to get the X/Y of a certain number =/ I'll try a bit more.

 

Orio.

[Millar]

Yeah. Surely it must be possible.

 

I just can't think of it either.

[Orio]

Well, I've built an algorithm that solves the problem, but I don't really like it because it's not a real mathematical solution... I was hoping to find a way to find the coordinates for a given number N in a mathematical way. But anyways, this solves the problem:

 

<?php

function get_coords($i)
{
$sqr_root = ceil(sqrt($i));
$sqr = $sqr_root * $sqr_root;
$i2 = ($i+$sqr_root <= $sqr) ? $i+$sqr_root-1 : $i;
$distance = $sqr - $i2;
if($i+$sqr_root <= $sqr)
	return "(".$sqr_root.", ".($sqr_root-$distance).")";
else
	return "(".($sqr_root-$distance).", ".$sqr_root.")";
}

for($i=1; $i<=36; $i++)
echo $i." = ".get_coords($i)."<br />";

?>

 

 

Orio.

[Millar]

Thankyou very much!

[Barand]

if you number like this

 

0  1  2  3
4  5  6  7
8  9 10 11
12 13 14 15

then

X coord = N%4
Y       = (int)N/4