local ffi = require "ffi" local math = require "math" local os = require "os" local xmath = require "xmath" local ldist = xmath.ldist local sqrt = math.sqrt local function printf(fmt, ...) print(string.format(fmt, ...)) end local function edist(p1, p2) return sqrt(p1.x*p1.x + p2.x*p2.x) end local vec2 = ffi.typeof("struct { int32_t x, y; }") local numpoints = 1e4 local Nsq = numpoints*numpoints printf("number of points: %d, testing %d distances", numpoints, Nsq) local B = 8192 local pts = {} for i=1,numpoints do pts[i] = vec2(math.random(-B, B), math.random(B, -B)) end -- test edist local t = os.clock() local sum = 0 for i=1,numpoints do for j=1,numpoints do sum = sum+edist(pts[i], pts[j]) end end t = os.clock()-t printf("edist: %.03fns per call, mean=%.03f", (1e9*t)/Nsq, sum/Nsq) -- test ldist t = os.clock() local sum = 0 for i=1,numpoints do for j=1,numpoints do sum = sum+ldist(pts[i], pts[j]) end end t = os.clock()-t printf("ldist: %.03fns per call, mean=%.03f", (1e9*t)/Nsq, sum/Nsq)