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Maths functions and random number generators
Other Standard Library features. example from a Well House Consultants training course
More on Other Standard Library features. [link] Source code: mathfuncs Module: U112
--[[ Lua has a rich range of maths functions which are illustrated here Random generators can produce integers or floats, and can be seeded to produce an everyvarying sequence, or the same sequence each time (for testing) ]] -- Returns the absolute value of x. x = -2.6 print ("Starting with " .. x) x = math.abs (x) print (x) -- Returns the cosine of x (assumed to be in radians). x = math.cos (x) print (x) -- Returns the arc cosine of x (in radians). x = math.acos (x) print (x) --[[ Returns the arc tangent of y/x (in radians), and uses the signs of both parameters to find the quadrant of the result. ]] y = 17.0 x = math.atan2 (y, x) print (x) -- Returns the smallest integer larger than or equal to x. x = math.ceil (x) print (x .. " ceiling ...") -- Returns the hyperbolic cosine of x. x = math.cosh (x) print (x) -- Returns the angle x (given in radians) in degrees. -- math.rad for reverse x = math.deg (x) print (x) x = math.rad(x) print (x) -- Returns the value ex. x = math.exp (x) print (x) -- Returns the largest integer smaller than or equal to x. x = math.floor (x) print (x .. " floor ...") -- Returns the remainder of the division of x by y. y=5 x = math.fmod (x, y) print (x) -- Returns the natural logarithm of x. x = math.log (x) print (x) -- Returns the base-10 logarithm of x. x = math.log10 (x) print (x) -- Returns the square root of x. x = math.sqrt (x) print (x) -- The value of pi. print (math.pi) -- x to power y. (You can also use the expression x^y to compute this value.) y=3 x = math.pow (x, y) print (x .. " power ...") print ("\nrandom reals") math.randomseed (x) -- to give same sequence each time dums = {} ost = "" for k=1,10 do dums[k] = math.random() ost = ost .. " / " .. dums[k] end print (ost) print ("\nrandom integers") math.randomseed(os.time()) -- sequence changes every second dums = {} ost = "" for k=1,10 do dums[k] = math.random(101,152) ost = ost .. " / " .. dums[k] end print (ost) --[[ ------------------- Sample Output [trainee@easterton u112]$ lua mathfuncs Starting with -2.6 2.6 -0.85688875336895 2.6 1.4190311714672 2 ceiling ... 3.7621956910836 215.5579348014 3.7621956910836 43.042831059009 43 floor ... 3 1.0986122886681 0.040844452568921 0.20210010531645 3.1415926535898 0.0082546681657717 power ... random reals / 0.84018771715471 / 0.39438292681909 / 0.78309922375861 / 0.79844003347607 / 0.91164735793678 / 0.19755136929338 / 0.33522275571489 / 0.7682295948119 / 0.27777471080319 / 0.55396995579543 random integers / 122 / 128 / 109 / 114 / 136 / 148 / 134 / 129 / 102 / 101 [trainee@easterton u112]$ ]] Learn about this subject
This module and example are covered on the following public courses:
* Learning to program in Lua * Lua Programming * Lua Programming Also available on on site courses for larger groups Books covering this topic
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