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Feb
27
comment Clarification on rings of polynomials / Galois fields
edit your answer to include the info about quotient rings + I'll accept.
Feb
25
comment Clarification on rings of polynomials / Galois fields
ah! Thanks, sounds like I should use something like GF2QuotientRing then. I appreciate it -- when I read formal mathematical documents I get lost in the thicket of terminology.
Feb
25
comment Clarification on rings of polynomials / Galois fields
OK, thanks. The objects I work have characteristic polynomials that are not always irreducible (e.g. not always a maximum-length LFSR). For the identifier I can only use alphanumeric characters, so I can't use GF(2,n) but I could use GaloisField. (GF would be frowned upon by software engineers for being too terse.)
Feb
18
comment solving linear diophantine equation with inequalities
whee! it worked, I posted a Python version of this in my question. Thanks!
Feb
17
comment solving linear diophantine equation with inequalities
e.g. in the original scaled lattice basis, if I had basis vectors $v_1$ and $v_2$, the continuous analog would be to compute $v_1' = v_1 - kv_2$ with $k = \frac{v_1 \cdot v_2}{v_2 \cdot v_2}$, so the integer version would be to find the nearest integer to k?
Feb
16
comment solving linear diophantine equation with inequalities
oh never mind, you meant this item from earlier in the post: "Repeatedly look for one vector that can be made shorter by adding or subtracting integer multiples of the other two"
Feb
16
comment solving linear diophantine equation with inequalities
Got all of that except the "You can reduce this (with a little work) to the basis" part... I don't need to see every step, but what's the basic methodology? Gram-Schmidt orthogonalization?
Feb
16
comment solving linear diophantine equation with inequalities
no, I get why there's extra space between the preceding text (between the k and mod in $ab \equiv k \mod m$) but don't understand about the space after the mod. Compare to $ab \equiv k \bmod m$.
Feb
16
comment solving linear diophantine equation with inequalities
Odd that the spacing between "mod" and "m" is so large with \mod, however. I should think that spacing would be the same for both \bmod and \mod, since the difference is really with the pause between the "mod" keyword and the stuff that comes before it.
Feb
16
comment solving linear diophantine equation with inequalities
ah.... so I really have some of each in this question. Fixing now...
Feb
16
comment solving linear diophantine equation with inequalities
Huh, thanks. I've got to digest this + see what I can make of it. I had been able to visualize the 2-D lattice, hadn't thought of adding a 3rd dimension to handle the modulus $m$, but I think I get the gist of what you're talking about.
Feb
16
comment solving linear diophantine equation with inequalities
hey, thanks! wait, when does the \mod form get used?
Feb
16
comment solving linear diophantine equation with inequalities
...and is there supposed to be that much space around ${\rm mod}$? If not, what should I be using for MathJax?
Feb
16
comment A sequence of 5 cards is drawn from a standard 52-card deck,with replacement. How many sequences will have at least one king or one queen, or both?
sounds correct to me.... replacement after each one?
Nov
9
comment Simple numerical methods for calculating the digits of $\pi$
that's easy: since the arctangent is a power series, convergence is dictated by the largest argument to the arctangent. In my case, it's 2/11.
Oct
15
comment How to move a body to a point using only velocity?
NJGUY: you still need to clarify your question. What do you mean by "move" ? Are you writing software to display something at certain points in time? Or do you just want to know the velocity (vx, vy) required to get an object from point (x1,y1) to point (x2,y2) in some time T?
Oct
15
comment How to move a body to a point using only velocity?
The writeup in Wikipedia of Bresenham's algorithm seems more complicated than it should, and also seems like it does not handle lines with steep slopes very well. This really shouldn't be that complicated. We also don't know whether NJGUY wants to draw individual pixels (in which case Bresenham's algorithm is a good match) or just wants to calculate an object's position at various positions in time. Whether you call it vector algebra or two parametric equations x = fx(t), y = fy(t), I still think it's simpler than trying to use time-independent algorithms.
Oct
15
comment How to move a body to a point using only velocity?
@RobertHarvey: no, you don't need the slope if you are using vector algebra.
Oct
15
comment How to move a body to a point using only velocity?
Please clarify your question. Is the second body's position fixed?
Mar
28
comment What comes after tetration ? And after ? And after ? etc.
the symbols didn't get displayed properly