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jmoenig / Snap

a visual programming language inspired by Scratch
http://snap.berkeley.edu
GNU Affero General Public License v3.0
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Increase digit accuracy (more than 16 digit precision) #621

Open itssumertime opened 9 years ago

itssumertime commented 9 years ago

Some students have math intensive projects that would greatly improve with greater digit precision. Some examples are RSA encryption and graphing calculators created in Snap.

cycomachead commented 9 years ago

Yesss. Admittedly this is a JS problem. See also #390 :)

cycomachead commented 9 years ago

Actually @itssumertime Do you know if this is a display issue or an calculations?

Numbers in JS are double-precision, which should be fine for most projects..I hope.

itssumertime commented 9 years ago

My students were using super large numbers that had more than 16 digits in them and doing modular math with them (for an RSA project), and when I asked what they did, they responded with "I am fairly sure it drops everything after the 16th digit to a 0. We haven't tried since we first started out, so I can't be 100% sure, but I believe what was happening was that the mods were coming back as 0 mod 2".

I think it means that the rough size of the number stayed but actual precise end digits were getting dropped.

itssumertime commented 9 years ago

Actually, he updated me and said that it does return incorrect calculations past a certain point and then "NaN" past another point, but it does seem to retain beyond 16 when checked with Wolfram|Alpha.

So I think you're right @cycomachead

cycomachead commented 9 years ago

Ah, ok. Gotcha. So bignums are something we should have in Snap! :)