fcbb7426fa
See #770 To help automatically translate code, see the zig-fmt-pointer-reform-2 branch. This will convert all & into *. Due to the syntax ambiguity (which is why we are making this change), even address-of & will turn into *, so you'll have to manually fix thes instances. You will be guaranteed to get compile errors for them - expected 'type', found 'foo'
66 lines
1.5 KiB
Zig
66 lines
1.5 KiB
Zig
const std = @import("std");
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const math = std.math;
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const Random = std.rand.Random;
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const ZigTable = struct {
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r: f64,
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x: [257]f64,
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f: [257]f64,
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pdf: fn (f64) f64,
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is_symmetric: bool,
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zero_case: fn (*Random, f64) f64,
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};
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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 {
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var tables: ZigTable = undefined;
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tables.is_symmetric = is_symmetric;
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tables.r = r;
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tables.pdf = f;
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tables.zero_case = zero_case;
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tables.x[0] = v / f(r);
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tables.x[1] = r;
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for (tables.x[2..256]) |*entry, i| {
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const last = tables.x[2 + i - 1];
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entry.* = f_inv(v / last + f(last));
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}
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tables.x[256] = 0;
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for (tables.f[0..]) |*entry, i| {
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entry.* = f(tables.x[i]);
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}
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return tables;
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}
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const norm_r = 3.6541528853610088;
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const norm_v = 0.00492867323399;
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fn norm_f(x: f64) f64 {
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return math.exp(-x * x / 2.0);
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}
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fn norm_f_inv(y: f64) f64 {
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return math.sqrt(-2.0 * math.ln(y));
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}
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fn norm_zero_case(random: *Random, u: f64) f64 {
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return 0.0;
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}
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const NormalDist = blk: {
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@setEvalBranchQuota(30000);
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break :blk ZigTableGen(true, norm_r, norm_v, norm_f, norm_f_inv, norm_zero_case);
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};
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test "bug 920 fixed" {
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const NormalDist1 = blk: {
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break :blk ZigTableGen(true, norm_r, norm_v, norm_f, norm_f_inv, norm_zero_case);
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};
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for (NormalDist1.f) |_, i| {
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std.debug.assert(NormalDist1.f[i] == NormalDist.f[i]);
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}
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}
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