From: "Shot (Piotr Szotkowski)" <shot@...>
Date: 2009-11-22T05:34:49+09:00
Subject: Re: Finding the closest value from a matrix

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Mahadev Ittina:

> I have a matrix that looks something like this

>        85        90       100       125        150         175
> 8     1.183    1.118     1.006     0.805      0.671      0.575
> 10    1.847    1.744     1.57      1.256      1.047      0.897
> 12    2.659    2.511      ..        ..           ...        ...
> 16    ...       ...        ..     ...           ...        ..

> Say, I have a value of 1.1, I want it to automatically choose the
> closest bigger value i.e. 1.118 and say 8 mm diameter at 90 mm
> spacing. How can this be implemented? I thought of creating hashes.
> but it seems too complicated. If anyone is wondering about the formula
> it goes like this.

> value =3D 2 x area of circle / spacing

Are the spacings restricted to 85, 90, 100, 125, 150 and 175?

Are the diameters restricted to 8, 10, 12 and 16?

Otherwise, do you have formul=C3=A6 for how the diameters and spacings grow?

Otherwise the matrix is so small that maybe
you can generate and search it on runtime:

diameters =3D [8, 10, 12, 16]
spacings  =3D [85, 90, 100, 125, 150, 175]
diameters.product(spacings).map { |d, s| [0.5 * Math::PI * d ** 2 / s, d, s=
] }.sort.find { |x,| x > 1.1 }
# =3D> [1.11701072127637, 8, 90]

=E2=80=94 Shot
--=20
I can picture in my mind a world without war, a world without hate. And
I can picture us attacking that world, because they=E2=80=99d never expect =
it.
                                                           [Jack Handy]

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