DoxigAlpha
std › Random › ziggurat.ZigTableGen

ZigTableGen

Function parameters

Parameters

#
is_symmetric:bool
r:f64
v:f64
f:fn (f64) f64
f_inv:fn (f64) f64
zero_case:fn (Random, f64) f64

Type definitions in this namespace

Types

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Functions in this namespace

Functions

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= blk: { @setEvalBranchQuota(30000); break :blk ZigTableGen(true, norm_r, norm_v, norm_f, norm_f_inv, norm_zero_case); }

Values

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NormDist
= blk: { @setEvalBranchQuota(30000); break :blk ZigTableGen(true, norm_r, norm_v, norm_f, norm_f_inv, norm_zero_case); }
norm_r
= 3.6541528853610088
norm_v
= 0.00492867323399
ExpDist
= blk: { @setEvalBranchQuota(30000); break :blk ZigTableGen(false, exp_r, exp_v, exp_f, exp_f_inv, exp_zero_case); }
exp_r
= 7.69711747013104972
exp_v
= 0.0039496598225815571993

Source

Implementation

#
pub fn ZigTableGen(
    comptime is_symmetric: bool,
    comptime r: f64,
    comptime v: f64,
    comptime f: fn (f64) f64,
    comptime f_inv: fn (f64) f64,
    comptime zero_case: fn (Random, f64) f64,
) ZigTable {
    var tables: ZigTable = undefined;

    tables.is_symmetric = is_symmetric;
    tables.r = r;
    tables.pdf = f;
    tables.zero_case = zero_case;

    tables.x[0] = v / f(r);
    tables.x[1] = r;

    for (tables.x[2..256], 0..) |*entry, i| {
        const last = tables.x[2 + i - 1];
        entry.* = f_inv(v / last + f(last));
    }
    tables.x[256] = 0;

    for (tables.f[0..], 0..) |*entry, i| {
        entry.* = f(tables.x[i]);
    }

    return tables;
}