Perl 130 chars So long as external libraries are permitted: use Algorithm::Permute”permute”; permute{for$x(@a=qw(+ – / *)){for$y(@a){$_=”@ARGV”;s/ /$x/;s/ /$y/;printf” $_ = %.0f”,eval}}}@ARGV 2nd newline is significant. Without a module, and assuming that all three inputs are distinct, here’s another solution: @n=& ARGV; @o=( q[+], “-“, q{/}, ‘*’ );; for$ {a}(@ n){ for $b(@n){for$c(@ {n}){ for $x( … Read more
First, let’s point out that SHA-256 does not accept all possible binary strings as input. As defined by FIPS 180-3, SHA-256 accepts as input any sequence of bits of length lower than 2^64 bits (i.e. no more than 18446744073709551615 bits). This is very common; all hash functions are somehow limited in formal input length. One … Read more
I created a Python package that attempts to implement the Kneedle algorithm. To recreate the function above and detect the point of maximum curvature: x = range(1,21) y = [0.065, 0.039, 0.030, 0.024, 0.023, 0.022, 0.019, 0.0185, 0.0187, 0.016, 0.015, 0.016, 0.0135, 0.0130, 0.0125, 0.0120, 0.0117, 0.0115, 0.0112, 0.013] kn = KneeLocator( x, y, curve=”convex”, … Read more
The problem described can be solved as follows. Let M = m_11 m_12 m_13 m_21 m_22 m_23 m_31 m_32 m_33 denote the desired rotation matrix. We require 1 0 0 * M + t = x_x x_y x_z 0 1 0 y_x y_y y_z 0 0 1 z_x z_y z_y where t denotes the translation; … Read more
As an alternative: <fmt:formatNumber var=”expiry” value=”${(expire.time – now.time) / (60 * 1000)}” maxFractionDigits=”0″ /> This way you do not lose localization (commas and dots).
Answer 1: it is Vector(x2-x1,y2-y1) Answer 2: Normalizing means to scale the vector so that its length is 1. It is a useful operation in many computations, for example, normal vectors should be specified normalized for lighting calculations in computer graphics. The normalized vector of v(x,y) is vn(x/Length(v), y/length(v)). HTH
First off, in most languages an undecorated constant like “1.55” is treated as a double precision value. However, 1.55 is not exactly representable as double precision value, because it doesn’t have a terminating representation in binary. This causes many curious behaviors, but one effect is that when you type 1.55, you don’t actually get the … Read more
If you want a list of college courses that you’ll need to understand the book, here it is: Calculus (I, II and III) Differential Equations Linear Algebra Statistics (or a good covering of Bayes) However, I did just fine in my NN classes without Diff. Eq. and just had to look up concepts I hadn’t … Read more
Because it is related to arctan(y/x), so y appears first. Here’s a nice link talking about it a bit: Angles and Directions
Here is a java program which uses a function that will return true if a latitude/longitude is found inside of a polygon defined by a list of lat/longs, with demonstration for the state of florida. I’m not sure if it deals with the fact that the lat/long GPS system is not an x/y coordinate plane. … Read more