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Posted by The Natural Philosopher on 01/19/08 19:57
itschy wrote:
> On 19 Jan., 17:19, The Natural Philosopher <a...@b.c> wrote:
>> itschy wrote:
>>> On 18 Jan., 23:31, Jensen Somers <jensen.som...@gmail.com> wrote:
>>>> PHP has support to create images, so my guess is - if I understand the
>>>> problem correctly - you'll just need to find a way to draw dots and
>>>> lines, making them thicker depending on the weight they have.
>>> Not quite.
>>> You missed the part, where I mentiond that I do not have any
>>> coordinates of the nodes. Thus I'cant just draw them, cause I don't
>>> know where. :)
>>> What I seek is some solution, which finds a representation according
>>> to the information I have about the edges (that is, connected or not,
>>> and if, what weight/line length do they have).
>>> E.g.:
>>> I have three nodes A,B,C and 3 connections a(A,B,3), b(B,C,4), c(A,C,
>>> 5) (each with infos about from_node, to_node and weight/length.
>>> In this szenario, there are only two possible ways to draw that
>>> network correctly:
>>> 5
>>> A-----C B
>>> 3\ /4 3/ \4
>>> B A-----C
>>> 5
>>> And their rotations.
>>> I try to find some tool/algorithm which is able to do this (and draw
>>> it) in php.
>>> Tough luck I guess... :(
>>> itschy
>> Didn't they teach you basic geometry at school?
>>
>> three nodes with three paths, defines a unique shape, which is constant.
>> It can be rotated and mirrored,without violating the original
>> definition, but the shape remains constant.
>>
>> To plot it, simply assume one point (A) is at 0,0, the next one - say
>> 'B' is at the correct distance along the X axis, so in your case its
>> co-ordinates are 3,0.
>>
>> Solving the position of the third point C involves solving a pair of
>> simultaneous quadratic equations. Cf Pythagoras and the dropping of
>> perpendiculars.
>>
>> Namely:-
>>
>> Cx^2+Cy^2=(5)^2
>> (3-Cx)^2 +Cy^2=(4)^2
>>
>> Now there are either two, or none, solutions for Cy as there always are
>> for quadratics. One solution is the mirror of the other.
>>
>> Now go solve it.
>>
>> Its your homework, not mine.
>
> Thanks for teaching me.
> Now, have you read anything I wrote?
> In short words i will summarize:
> 0. They did not only teach me basic geometry in school, but also
> analytical geometry, graph theory and such in university.
> 1. I try to find an EXISTING solution not write my own.
> 2. Jensen Somers misunderstood my initial post, so I clarified, what
> kind of solution I seek. I described to him exactly what you did to me
> (in a visual way).
> 3. I know well how to do it, I wanted to know if it was done before
> (because with all the drwaing stuff it is not worth it to implement it
> by myself)
> 4. Your answer is still welcome, maybe someone searching and finding
> this thread can use it. but next time please don't assume everyone
> else is stupid! :)
I don't assume. I go on the evidence.
Maths packages exist.
Graphics packages exists.
The mathematics of quadratics is well known.
So all it needs s an unstupid unlazy person to put them all together.
Php doesn't have a package to calculate the net loss in weight of a
rutting elephant after sex, either.
If you want soenmthing that obscure, write it.
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