Random numbers: Difference between revisions

=={{header|Avail}}==

<lang Avail>Method "U(_,_)" is

[

lower : number,

upper : number

|

divisor ::= ((1<<32)) ÷ (upper - lower)→double;

map a pRNG through [i : integer | (i ÷ divisor) + lower]

];

Method "a Marsaglia polar sampler" is

[

generator for

[

yield : [double]→⊤

|

source ::= U(-1, 1);

Repeat [

x ::= take 1 from source[1];

y ::= take 1 from source[1];

s ::= x^2 + y^2;

If 0 < s < 1 then

[

factor ::= ((-2 × ln s) ÷ s) ^ 0.5;

yield(x × factor);

yield(y × factor);

];

]

]

];

// the default distribution has mean 0 and std dev 1.0, so we scale the values

sampler ::= map a Marsaglia polar sampler through [d : double | d ÷ 2.0 + 1.0];

values ::= take 1000 from sampler;</lang>