thelastpenguin

# ref: https://github.com/prasmussen/gdrive

# prerequisite:
#  In google drive, setup your folder for storing the backups
#  Then grab the code from the url e.g. https://drive.google.com/drive/folders/xxxxx where xxxxx is the code
#  This code will be used later in the cron command, keep it secret, keep it safe

# install gdrive sync for backups
wget https://drive.google.com/uc?id=0B3X9GlR6EmbnQ0FtZmJJUXEyRTA -O /usr/local/bin/gdrive
chmod 755 /usr/local/bin/gdrive

thelastpenguin

-- l0 is the origin of the line
-- l is the direction of the line expressed as a normal vector (tbd: does it have to be normal? possibly not)
-- p0 is the origin of the plane 
-- n is a vector orthogonal to the surface of the plane expressed as a normal vector (tbd: does it have to be normal? possibly not)
function vectorIntersectPlane(l0, l, p0, n)
    -- we find d by substituting the equation for the line into the equation of the plane and solving for d
    d = (p0 - l0):Dot(n) / l:Dot(n) -- distance along the line at which the line intersects the plane 
    
    -- the point of intersection is found by substituting the distance back into the line equation
    -- p = dl + l0 

thelastpenguin

local hashtable = (function()
    local hashtable_mt = {}
    hashtable_mt.__index = hashtable_mt 

    local primes = {53, 97, 193, 389, 769, 1543, 3079, 6151, 12289, 24593, 49157, 98317, 196613, 393241, 786433, 1572869, 3145739, 6291469, 12582917, 25165843, 50331653, 100663319, 201326611, 402653189, 805306457, 1610612741}
    local empty = {}

    function hashtable() 
        local ht = {
            data = {},