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Module:Utils: Difference between revisions

Fredg999 (talk | contribs)
autopatrolled, Interface administrators, Sysops
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Started a (general math) utils module, with log(x, b) and round(x, p) functions so far. Let's hope it works as expected.
 
ArrowHead294 (talk | contribs)
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mNo edit summary
 
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local p = {}
local p = {}


-- return logarithm base b of x
local get_args = require("Module:Arguments").getArgs
local function log(x, b)
local yesno = require("Module:Yesno")
b = b or 2 -- defaults to base 2 (octave) if b is omitted
 
return math.log(x)/math.log(b)
-- Trim a string (remove leading and trailing, but not interior, whitespace)
function p.trim(s)
  return s:match("^%s*(.-)%s*$")
end
 
-- Wrapper function for template access to [[Module:Yesno]]
function p._yesno(frame)
return yesno(frame.args["input"], frame.args["default"])
end
 
-- Check if a table contains x
function p.table_contains(tbl, x)
for i = 1, #tbl do
if x == tbl[i] then
return true
end
end
return false
end
end


-- return x rounded to a precision of p decimal places
-- Return the first index with the given value (or nil if not found)
local function round(x, p)
function p.index_of(array, value)
p = p or 3 -- default to 3 decimal places if p is omitted
for i, v in ipairs(array) do
return math.floor(x*10^p+0.5)/10^p
if v == value then
return i
end
end
return nil
end
end


return p;
-- Check whether the input is a non-empty string
function p.value_provided(s)
return type(s) == "string" and #s > 0
end
 
-- Evaluate input on error use default; cannot be used with {{#invoke:}}
function p.eval_num_arg(input, def_value)
local result = input
if type(input) ~= "number" then
result = def_value
if type(input) == "string" then
-- Check for fraction notation
if input:match("/") == "/" then
local numerator, denominator = input:match("^%s*([0-9]+)[/?]([0-9]+)%s*$")
result = (tonumber(numerator) or def_value) / (tonumber(denominator) or 1)
else
result = tonumber(input)
end
end
end
return result
end
 
-- Return logarithm base b of x
function p.log(frame)
local args = get_args(frame)
return p._log(args[1], args[2])
end
 
local LN_2 = math.log(2)
-- Return logarithm base 2 of x
function p.log2(x)
return math.log(x) / LN_2
end
 
function p._log(x, b)
-- x defaults to 0
x = p.eval_num_arg(x, 0)
-- b defaults to 2 ("octave")
b = p.eval_num_arg(b, 2)
return math.log(x) / math.log(b)
end
 
-- Return greatest common divisor of a and b
function p.gcd(frame)
local args = get_args(frame)
return p._gcd(args[1], args[2])
end
 
function p._gcd(a, b)
if b ~= 0 then
return p._gcd(b, a % b)
else
return math.abs(a)
end
end
 
-- Return x rounded to places decimal places
function p.round_dec(frame)
local args = get_args(frame)
return p._round_dec(args[1], args[2])
end
 
function p._round_dec(x, places)
-- x defaults to 0
x = p.eval_num_arg(x, 0)
-- places defaults to 0
places = p.eval_num_arg(places, 0)
return math.floor(x * 10 ^ places + 0.5) / 10 ^ places
end
 
-- Return x rounded to a precision of prec significant figures
function p.round(frame)
local args = get_args(frame)
return p._round(args[1], args[2])
end
 
function p._round(x, prec)
-- x defaults to 0
x = p.eval_num_arg(x, 0)
-- prec defaults to 6
prec = p.eval_num_arg(prec, 6)
if x == 0 then
return 0
else
return p._round_dec(x, prec - math.floor(p._log(math.abs(x), 10)) - 1)
end
end
 
-- Cached list of primes for is_prime
local primes_cache = {
[0] = false,
[1] = false,
}
 
-- Returns true if integer n is prime; cannot be used with {{#invoke:}}
function p.is_prime(n)
local cached = primes_cache[n]
if cached ~= nil then
return cached
end
for i = 2, math.sqrt(n) do
if n % i == 0 then
primes_cache[n] = false
return false
end
end
primes_cache[n] = true
return true
end
 
-- Returns prime factorization of integer n > 1; cannot be used with {{#invoke:}}
-- Note: the order of keys is not specified for Lua tables
function p.prime_factorization_raw(n)
local factors = {}
local m = n
for i = 2, math.sqrt(n) + 1 do
while m % i == 0 do
factors[i] = factors[i] or 0
factors[i] = factors[i] + 1
m = m / i
end
if m == 1 then
break
end
end
if m > 1 then
factors[m] = factors[m] or 1
end
return factors
end
 
-- Returns prime factorization of integer n > 2 (with wiki markup for exponents)
function p.prime_factorization(frame)
local args = get_args(frame)
return p._prime_factorization(p.eval_num_arg(args[1], 12)) -- default to 12
end
 
function p._prime_factorization(n)
if n <= 1 then
return "n/a"
end
local factors, powers = {}, {}
local new_number = n
for i = 2, n do
if p.is_prime(i) then
if new_number % i == 0 then
factors[#factors + 1] = i
powers[#factors] = 0
while new_number % i == 0 do
powers[#factors] = powers[#factors] + 1
new_number = new_number / i
end
if powers[#factors] > 1 then
powers[#factors] = factors[#factors] .. "<sup>" .. powers[#factors] .. "</sup>"
else
powers[#factors] = factors[#factors]
end
end
end
if new_number == 1 then
break
end
end
return table.concat(powers, " × ")
end
 
-- Returns signum(x); cannot be used with {{#invoke:}}
function p.signum(x)
if type(x) ~= "number" then
return 0
end
if x > 0 then
return 1
end
if x < 0 then
return -1
end
return 0
end
 
-- Returns the next Young diagram of the same size or nil; cannot be used with {{#invoke:}}
-- Modifies the input table
function p.next_young_diagram(d)
if #d == 0 then
return nil
end
local i_from = nil
local size = 0
for i = #d, 1, -1 do
if d[i] > 1 then
i_from = i
break
end
size = size + d[i]
end
if i_from == nil then
return nil
end
d[i_from] = d[i_from] - 1
size = size + 1
-- repacking the tail
local max_d = d[i_from]
for i = i_from + 1, #d + 1 do
if size >= max_d then
d[i] = max_d
size = size - max_d
elseif size > 0 then
d[i] = size
size = 0
else
d[i] = nil
end
end
return d
end
 
-- stylua: ignore
p.primes = {2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97,
  101, 103, 107, 109, 113, 127, 131, 137, 139, 149, 151, 157, 163, 167, 173, 179, 181, 191, 193, 197, 199,
  211, 223, 227, 229, 233, 239, 241, 251, 257, 263, 269, 271}
 
return p
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