Code: Select all
--- Random String Generator.
-- Learns from provided strings, and generates similar strings.
-- @module ROT.StringGenerator
local ROT = require((...):gsub(('.[^./\\]*'):rep(1) .. '$', ''))
local StringGenerator = ROT.Class:extend("StringGenerator")
--- Constructor.
-- Called with ROT.StringGenerator:new()
-- @tparam table options A table with the following fields:
-- @tparam[opt=false] boolean options.words Use word mode
-- @tparam[opt=3] int options.order Number of letters/words to be used as context
-- @tparam[opt=0.001] number options.prior A default priority for characters/words
function StringGenerator:init(options)
self._options = {words=false,
order=3,
prior=0.001
}
self._boundary=string.char(0)
self._suffix =string.char(0)
self._prefix ={}
self._priorValues={}
self._data ={}
if options then
for k,v in pairs(options) do
self._options[k]=v
end
end
for _=1,self._options.order do
table.insert(self._prefix, self._boundary)
end
self._priorValues[self._boundary]=self._options.prior
end
--- Remove all learned data
function StringGenerator:clear()
self._data={}
self._priorValues={}
end
--- Generate a string
-- @treturn string The generated string
function StringGenerator:generate()
local result={self:_sample(self._prefix)}
while result[#result] ~= self._boundary do
table.insert(result, self:_sample(result))
end
table.remove(result)
return table.concat(result)
end
--- Observe
-- Learn from a string
-- @tparam string s The string to observe
function StringGenerator:observe(s)
local tokens = self:_split(s)
for i=1,#tokens do
self._priorValues[tokens[i]] = self._options.prior
end
local i=1
for _,v in pairs(self._prefix) do
table.insert(tokens, i, v)
i=i+1
end
table.insert(tokens, self._suffix)
for i=self._options.order,#tokens-1 do
local context=table.slice(tokens, i-self._options.order+1, i)
local evt = tokens[i+1]
for j=1,#context do
local subcon=table.slice(context, j)
self:_observeEvent(subcon, evt)
end
end
end
--- get Stats
-- Get info about learned strings
-- @treturn string Number of observed strings, number of contexts, number of possible characters/words
function StringGenerator:getStats()
local parts={}
local prC=0
for _ in pairs(self._priorValues) do
prC = prC + 1
end
prC=prC-1
table.insert(parts, 'distinct samples: '..prC)
local dataC=0
local evtCount=0
for k,_ in pairs(self._data) do
dataC=dataC+1
for _,_ in pairs(self._data[k]) do
evtCount=evtCount+1
end
end
table.insert(parts, 'dict size(cons): '..dataC)
table.insert(parts, 'dict size(evts): '..evtCount)
return table.concat(parts, ', ')
end
function StringGenerator:_split(str)
return str:split(self._options.words and " " or "")
end
function StringGenerator:_join(arr)
return table.concat(arr, self._options.words and " " or "")
end
function StringGenerator:_observeEvent(context, event)
local key=self:_join(context)
if not self._data[key] then
self._data[key] = {}
end
if not self._data[key][event] then
self._data[key][event] = 0
end
self._data[key][event]=self._data[key][event]+1
end
function StringGenerator:_sample(context)
context =self:_backoff(context)
local key =self:_join(context)
local data=self._data[key]
local avail={}
if self._options.prior then
for k,_ in pairs(self._priorValues) do
avail[k] = self._priorValues[k]
end
for k,_ in pairs(data) do
avail[k] = avail[k]+data[k]
end
else
avail=data
end
return self:_pickRandom(avail)
end
function StringGenerator:_backoff(context)
local ctx = {}
for i=1,#context do ctx[i]=context[i] end
if #ctx > self._options.order then
while #ctx > self._options.order do table.remove(ctx, 1) end
elseif #ctx < self._options.order then
while #ctx < self._options.order do table.insert(ctx,1,self._boundary) end
end
while not self._data[self:_join(ctx)] and #ctx>0 do
ctx=table.slice(ctx, 2)
end
return ctx
end
function StringGenerator:_pickRandom(data)
local total =0
for k,_ in pairs(data) do
total=total+data[k]
end
local rand=self._rng:random()*total
local i=0
for k,_ in pairs(data) do
i=i+data[k]
if (rand<i) then
return k
end
end
end
return StringGenerator
Code: Select all
class StringGenerator{
Hashset data
![Cry :cry:](./images/smilies/ms-cry.png)
If it's to big to translate, you could give me pointers on where to start
![Smile :)](./images/smilies/ms-smile.png)