nlua_rnd.c File Reference

Lua bindings for the Naev random number generator. More...

#include "nlua_rnd.h"
#include "nluadef.h"
#include "rng.h"

Include dependency graph for nlua_rnd.c:

Go to the source code of this file.

Functions
static int	rndL_int (lua_State *L)
	Bindings for interacting with the random number generator.
static int	rndL_sigma (lua_State *L)
	Creates a number in the one-sigma range [-1:1].
static int	rndL_twosigma (lua_State *L)
	Creates a number in the two-sigma range [-2:2].
static int	rndL_threesigma (lua_State *L)
	Creates a number in the three-sigma range [-3:3].
static int	rndL_uniform (lua_State *L)
	Gets a random number in the given range, with a uniform distribution.
static int	rndL_angle (lua_State *L)
	Gets a random angle, i.e., a random number from 0 to 2*pi.
static int	rndL_permutation (lua_State *L)
	Creates a random permutation.
int	nlua_loadRnd (nlua_env env)
	Loads the Random Number Lua library.

Variables
static const luaL_Reg	rnd_methods []

Detailed Description

Lua bindings for the Naev random number generator.

Definition in file nlua_rnd.c.

Function Documentation

nlua_loadRnd()

int nlua_loadRnd

(

nlua_env

env

)

Loads the Random Number Lua library.

Parameters

env	Lua environment.

Returns

0 on success.

Definition at line 43 of file nlua_rnd.c.

rndL_angle()

int rndL_angle ( lua_State * L )

static

Gets a random angle, i.e., a random number from 0 to 2*pi.

Lua usage parameter: vec2.newP(radius, rnd.angle()) Lua return parameter: number A randomly generated angle, in radians.

Parameters

L

Lua State

Returns

Number of variables on the Lua State stack.

Lua function: angle

Definition at line 202 of file nlua_rnd.c.

rndL_int()

int rndL_int ( lua_State * L )

static

Bindings for interacting with the random number generator.

This module not only allows basic random number generation, but it also handles more complicated statistical stuff.

Example usage would be:

if rnd.rnd() < 0.5 then
   -- 50% chance of this happening
else
   -- And 50% chance of this happening
end

Lua module: rnd

Gets a random number. With no parameters it returns a random float between 0 and 1.

With one parameter it returns a whole number between 0 and that number (both included). With two parameters it returns a whole number between both parameters (both included).

Lua usage parameter: n = rnd() – Number in range [0:1]. Lua usage parameter: n = rnd(5) – Number in range [0:5]. Lua usage parameter: n = rnd(3,5) – Number in range [3,5].

Lua function parameter: number x First parameter, read description for details. Lua function parameter: number y Second parameter, read description for details. Lua return parameter: number A randomly generated number, read description for details.

Parameters

L

Lua State

Returns

Number of variables on the Lua State stack.

Lua function: rnd

Definition at line 84 of file nlua_rnd.c.

rndL_permutation()

int rndL_permutation ( lua_State * L )

static

Creates a random permutation.

This creates a list from 1 to input and then randomly permutates it, however, if an ordered table is passed as a parameter, that is randomly permuted instead.

Lua usage parameter: t = rnd.permutation( 5 ) Lua usage parameter: t = rnd.permutation( {"cat", "dog", "cheese"} )

Lua function parameter: number|table input Maximum value to permutate to. Lua return parameter: table A randomly permutated table.

Parameters

L

Lua State

Returns

Number of variables on the Lua State stack.

Lua function: permutation

Definition at line 222 of file nlua_rnd.c.

rndL_sigma()

int rndL_sigma ( lua_State * L )

static

Creates a number in the one-sigma range [-1:1].

A one sigma range means that it creates a number following the normal distribution but limited to the 63% quadrant. This means that the number is biased towards 0, but can become either 1 or -1. It's a fancier way of generating random numbers.

Lua usage parameter: n = 5.5 + rnd.sigma()/2. – Creates a number from 5 to 6 slightly biased to 5.5. Lua return parameter: number A number from [-1:1] biased slightly towards 0.

Parameters

L

Lua State

Returns

Number of variables on the Lua State stack.

Lua function: sigma

Definition at line 117 of file nlua_rnd.c.

rndL_threesigma()

int rndL_threesigma ( lua_State * L )

static

Creates a number in the three-sigma range [-3:3].

This function behaves much like its brothers rnd.sigma and rnd.twosigma. The main difference is that it uses the three-sigma range which is the 99% quadrant. It will rarely generate numbers outside the [-2:2] range (about 5% of the time) and create numbers outside of the [-1:1] range about 37% of the time. This can be used when you want extremes to appear rarely.

Lua usage parameter: n = 5.5 + rnd.threesigma()/6. – Creates a number from 5 to 6 totally biased to 5.5.

Lua return parameter: number A number from [-3:3] biased totally towards 0.

Parameters

L

Lua State

Returns

Number of variables on the Lua State stack.

Lua function: threesigma

Definition at line 156 of file nlua_rnd.c.

rndL_twosigma()

int rndL_twosigma ( lua_State * L )

static

Creates a number in the two-sigma range [-2:2].

This function behaves much like the rnd.sigma function but uses the two-sigma range, meaning that numbers are in the 95% quadrant and thus are much more random. They are biased towards 0 and approximately 63% will be within [-1:1]. The rest will be in either the [-2:-1] range or the [1:2] range.

Lua usage parameter: n = 5.5 + rnd.twosigma()/4. – Creates a number from 5 to 6 heavily biased to 5.5.

Lua return parameter: number A number from [-2:2] biased heavily towards 0.

Parameters

L

Lua State

Returns

Number of variables on the Lua State stack.

Lua function: twosigma

Definition at line 136 of file nlua_rnd.c.

rndL_uniform()

int rndL_uniform ( lua_State * L )

static

Gets a random number in the given range, with a uniform distribution.

Lua usage parameter: n = uniform() – Real number in the interval [0,1]. Lua usage parameter: n = uniform(5) – Real number in the interval [0,5]. Lua usage parameter: n = uniform(3,5) – Real number in the interval [3,5].

Lua function parameter: number x First parameter, read description for details. Lua function parameter: number y Second parameter, read description for details. Lua return parameter: number A randomly generated number, read description for details.

Parameters

L

Lua State

Returns

Number of variables on the Lua State stack.

Lua function: uniform

Definition at line 175 of file nlua_rnd.c.

Variable Documentation

rnd_methods

const luaL_Reg rnd_methods[]

static

Initial value:

= { { "rnd", rndL_int },
                                        { "sigma", rndL_sigma },
                                        { "twosigma", rndL_twosigma },
                                        { "threesigma", rndL_threesigma },
                                        { "uniform", rndL_uniform },
                                        { "angle", rndL_angle },
                                        { "permutation", rndL_permutation },
                                        { 0, 0 } }

Random Lua methods.

Definition at line 28 of file nlua_rnd.c.