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Merged
merged 2 commits into from Nov 24, 2018
Merged

Added Tangents-to-two-circles #366

merged 2 commits into from Nov 24, 2018

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ghost
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@ghost ghost commented Nov 22, 2018

Translated the original page found at : http://e-maxx.ru/algo/circle_tangents using google translate. Made some minor changes preserving the original text and added image and use of TEX for formulas.

@jakobkogler jakobkogler self-assigned this Nov 23, 2018
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Thanks at bunch.
Great job.
I fixed a few little things, but otherwise everything looks good.

One question for legal reasons before I merge the article: did you draw the picture yourself?

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ghost commented Nov 23, 2018

Yeah. I can provide the source.ai file (if required).

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Great.

I version-controll all files necessary for creating images under e-maxx-eng-aux. It has already happened that an image contained an error, with this repo I can quickly change images.

If you want you can add your source.ai file there as well, but you don't have to.

@jakobkogler jakobkogler merged commit f8aa3c6 into cp-algorithms:master Nov 24, 2018
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ghost commented Nov 24, 2018

Thanks.

I have made a PR, adding the .ai and .png files for future use. pr link

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ghost commented Nov 24, 2018

Can you please fix the image in the page? Link

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@Forgotter Done. I simply resized the image with HTML.
Not a good solution, however, since the text in the image is now too small. If it isn't too much work, you could change the image to 2 columns/3 rows instead of 3 columns/2 rows. This should make it more readable.

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ghost commented Nov 26, 2018

Thanks.
Since, you've mentioned the width of page, i've resized the new image accordingly and reverted back html used, here's the link to pr #369 .

Besides, I wanted to contribute an article on integer factorization and finding prime numbers, I'm not sure how well I can explain things (I'm not an expert) and don't know if the article could be of quality that cp-algorithms has been delivering. Will it be okay, if I write one and then interested people can improve upon it? If yes, I shall start this weekend after my exams get over.

It's hard to find good articles for both of them (Covering the range from smaller integers to integers of higher order).

Also, I was thinking, if those peoples having good articles on codeforces can rewrite the same for cp-algorithms. That would be great.

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@Forgotter Thanks. I'll take at look at #369 at the evening.

Yes, you can contribute original articles to the project. And it doesn't matter if they are complete or not.

However, I've already started translating the article http://e-maxx.ru/algo/factorization, (well mostly written it new from scratch since the article doesn't explain anything at all and the implementations are a little wonky). I started a month ago, but then took a break and now almost forgot about it. It probably makes not much sense if we both work on the same article alone and end up with two identical articles. I'll send you the current state of my article at the evening. Currently it contains trivial factorization until sqrt n, simple speedups like wheel factorization and precomputing primes, and Pollard's p-1 factorization. I think I've also started with Pollard's rho algorithm and Bent's modification. Maybe you can take a look at my current article, and extend it. I also don't have the most knowledge about integer factorization, so it would be good if you could help.

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@Forgotter As promised, here is my current status of the factorization part:
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I completely forgot how much work I already put into this article. I should really finish and publish it.

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ghost commented Nov 27, 2018

You have done a lot of work already. It'll be good if you can make a test like BPSW out of already implemented routines, and then publish the article.

However, there are few more algorithms I would like to see like Shank's Square form, Lenstra elliptic curve (I don't know this) and General Number Field Sieve (I don't know this either).

And yeah, a benchmark analysis for all mentioned implementation will be good to have.

P.S. In line just before the pollard-rho's code, there's a typo for $10^{18}$. And yeah, It will be a better idea to use primality tests to check if number itself is a prime or the factors returned are prime.

Here's link to my old code to factorize upto using pollard rho $10^{19}$ Link . I shall be improving it to deal upto $10^{30}$ shortly.

I shall see to whatever I can contribute starting this weekend.

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