ingot-lean-zig / zig /lean.zig
ego0op's picture
Add workbook config: 1,208 proved Lean-Workbook integer statements converted by the rule-based lean2zig converter, each re-verified with zig test
2789d27 verified
Raw History Blame Contribute Delete
10.9 kB
//! Lean 4 integer semantics for the lean2zig converter (Lean-Workbook / OProofs subset).
//! Every value is an i128. Naturals are non-negative i128; the type only decides which operator
//! (`sub`/`monus`) the converter emits. Overflow and undecided searches never fail a vector: they set a
//! flag, `skipped()` reports it, and the test skips that vector.
const std = @import("std");
/// Vectors tried per theorem, and per theorem with a loop (quantifier or finite sum) in it.
pub const tries: usize = 1500;
pub const tries_heavy: usize = 240;
/// Upper end of an unbounded natural variable's draw range.
pub const top: i128 = 1 << 24;
/// Longest finite range a quantifier or a sum may walk; longer ones skip the vector.
pub const span_cap: i128 = 4096;
threadlocal var overflowed: bool = false;
threadlocal var undecided: bool = false;
pub fn begin() void {
overflowed = false;
undecided = false;
}
threadlocal var skip_count: usize = 0;
pub fn skipped() bool {
if (overflowed or undecided) {
skip_count += 1;
return true;
}
return false;
}
/// Marks the current vector as not decided (a truncated search ran out). Returns true so it can sit in a bool expression.
pub fn giveUp() bool {
undecided = true;
return true;
}
fn overflow() i128 {
overflowed = true;
return 0;
}
pub fn add(a: i128, b: i128) i128 {
const r = @addWithOverflow(a, b);
return if (r[1] != 0) overflow() else r[0];
}
pub fn sub(a: i128, b: i128) i128 {
const r = @subWithOverflow(a, b);
return if (r[1] != 0) overflow() else r[0];
}
pub fn mul(a: i128, b: i128) i128 {
const r = @mulWithOverflow(a, b);
return if (r[1] != 0) overflow() else r[0];
}
pub fn neg(a: i128) i128 {
return sub(0, a);
}
/// Natural-number subtraction: truncates at 0.
pub fn monus(a: i128, b: i128) i128 {
return if (a < b) 0 else sub(a, b);
}
/// Int.emod / Nat.mod: x % 0 = x, otherwise the remainder in [0, |b|).
pub fn mod(a: i128, b: i128) i128 {
if (b == 0) return a;
if (b == std.math.minInt(i128) or a == std.math.minInt(i128)) return overflow();
return @mod(a, if (b < 0) -b else b);
}
/// Int.ediv / Nat.div: x / 0 = 0, otherwise the quotient matching `mod`.
pub fn div(a: i128, b: i128) i128 {
if (b == 0) return 0;
if (b == std.math.minInt(i128) or a == std.math.minInt(i128)) return overflow();
return @divExact(a - mod(a, b), b);
}
pub fn pow(b: i128, e: i128) i128 {
if (e < 0) return overflow();
if (e == 0) return 1;
if (b == 0 or b == 1) return b;
if (b == -1) return if (@mod(e, 2) == 0) 1 else -1;
if (e > 127) return overflow();
var r: i128 = 1;
var i: i128 = 0;
while (i < e) : (i += 1) r = mul(r, b);
return r;
}
pub fn abs(a: i128) i128 {
return if (a < 0) neg(a) else a;
}
/// Int.toNat.
pub fn toNat(a: i128) i128 {
return if (a < 0) 0 else a;
}
pub fn gcd(a: i128, b: i128) i128 {
const ua = abs(a);
const ub = abs(b);
if (ua == 0 and ub == 0) return 0;
if (ua <= std.math.maxInt(u64) and ub <= std.math.maxInt(u64)) return std.math.gcd(@as(u64, @intCast(ua)), @as(u64, @intCast(ub)));
var x = ua;
var y = ub;
while (y != 0) {
const t = @mod(x, y);
x = y;
y = t;
}
return x;
}
pub fn lcm(a: i128, b: i128) i128 {
if (a == 0 or b == 0) return 0;
return mul(div(abs(a), gcd(a, b)), abs(b));
}
pub fn choose(n: i128, k: i128) i128 {
if (n < 0 or k < 0 or k > n) return 0;
const m = @min(k, n - k);
var r: i128 = 1;
var i: i128 = 1;
while (i <= m) : (i += 1) {
r = div(mul(r, n - m + i), i);
if (overflowed) return 0;
}
return r;
}
pub fn factorial(n: i128) i128 {
if (n < 0) return overflow();
if (n > 40) return overflow();
var r: i128 = 1;
var i: i128 = 2;
while (i <= n) : (i += 1) r = mul(r, i);
return r;
}
pub fn fib(n: i128) i128 {
if (n < 0 or n > 180) return overflow();
var a: i128 = 0;
var b: i128 = 1;
var i: i128 = 0;
while (i < n) : (i += 1) {
const t = add(a, b);
a = b;
b = t;
}
return a;
}
pub fn isqrt(n: i128) i128 {
if (n <= 0) return 0;
var r: i128 = @intFromFloat(@sqrt(@as(f64, @floatFromInt(n))));
while (r * r > n) r -= 1;
while ((r + 1) * (r + 1) <= n) r += 1;
return r;
}
pub fn isPrime(n: i128) bool {
if (n < 2) return false;
if (n > 10_000_000_000) return giveUp();
const m: u64 = @intCast(n);
if (m < 4) return true;
if (m % 2 == 0) return false;
var d: u64 = 3;
while (d * d <= m) : (d += 2) {
if (m % d == 0) return false;
}
return true;
}
/// Nat.totient, by trial-division factorisation.
pub fn totient(n: i128) i128 {
if (n <= 0) return 0;
if (n > 10_000_000_000) return overflow();
var m: u64 = @intCast(n);
var r: u64 = m;
var p: u64 = 2;
while (p * p <= m) : (p += 1) {
if (m % p == 0) {
while (m % p == 0) m /= p;
r -= r / p;
}
}
if (m > 1) r -= r / m;
return r;
}
/// a ∣ b (Nat or Int): 0 ∣ b only when b = 0.
pub fn dvd(a: i128, b: i128) bool {
if (a == 0) return b == 0;
return mod(b, a) == 0;
}
/// a ≡ b [ZMOD n] and a ≡ b [MOD n].
pub fn modeq(a: i128, b: i128, n: i128) bool {
return mod(a, n) == mod(b, n);
}
/// True when lo..hi is short enough to walk; otherwise marks the vector undecided.
pub fn spanOk(lo: i128, hi: i128) bool {
if (hi < lo) return true;
if (hi - lo > span_cap) return !giveUp();
return true;
}
/// Deterministic generator: edge values, values at the range ends, then small, medium and large draws.
pub const Rng = struct {
state: u64,
const edges = [_]i128{ 0, 1, -1, 2, -2, 3, 4, 5, 7, -3, 6, 8, 9, 10, 11, 12, 13, 16, 17, 19, 23, 31, 64, 97, 100, 101, 127, 256, 1000, 1009 };
pub fn init(seed: u64) Rng {
return .{ .state = seed *% 0x9E3779B97F4A7C15 +% 0x1234567 };
}
fn next(self: *Rng) u64 {
self.state +%= 0x9E3779B97F4A7C15;
var z = self.state;
z = (z ^ (z >> 30)) *% 0xBF58476D1CE4E5B9;
z = (z ^ (z >> 27)) *% 0x94D049BB133111EB;
return z ^ (z >> 31);
}
fn window(self: *Rng, lo: i128, hi: i128, wlo: i128, whi: i128) i128 {
var a = @max(lo, wlo);
var b = @min(hi, whi);
if (a > b) {
if (hi < wlo) {
a = @max(lo, hi - (whi - wlo));
b = hi;
} else {
a = lo;
b = @min(hi, lo + (whi - wlo));
}
}
const span: u64 = @intCast(@min(b - a + 1, std.math.maxInt(u32)));
return a + @as(i128, self.next() % span);
}
/// A value in lo..hi, or null when the range is empty.
pub fn pick(self: *Rng, lo: i128, hi: i128) ?i128 {
if (lo > hi) return null;
switch (self.next() % 10) {
0, 1, 2 => {
const e = edges[self.next() % edges.len];
if (e >= lo and e <= hi) return e;
return self.window(lo, hi, -20, 30);
},
3 => {
const d: i128 = @intCast(self.next() % 3);
return if (self.next() & 1 == 0) @min(hi, lo + d) else @max(lo, hi - d);
},
4, 5, 6 => return self.window(lo, hi, -20, 30),
7, 8 => return self.window(lo, hi, -1000, 1000),
else => return self.window(lo, hi, -1_000_000, 1_000_000),
}
}
};
/// Vector source: first an exhaustive grid of small values over the free variables (so equalities with small solutions are
/// found), then edge-weighted random draws. Each loop iteration draws its variables in order with `pick`.
pub const Source = struct {
rng: Rng,
base: u64,
grid_total: usize,
total: usize,
step: usize = 0,
slot: usize = 0,
/// k = number of free variables; heavy statements (loops inside) skip the grid and run fewer random vectors.
pub fn init(seed: u64, k: usize, heavy: bool) Source {
// Largest base whose k-th power stays within the grid budget; no grid for loop-heavy statements or many variables.
var base: u64 = 128;
var grid: usize = 1;
while (base >= 3) : (base -= if (base > 24) 8 else 1) {
grid = 1;
for (0..k) |_| grid = std.math.mul(usize, grid, base) catch 1 << 40;
if (grid <= 12000) break;
grid = 1;
}
if (heavy or base < 3 or grid > 12000) grid = 0;
return .{ .rng = Rng.init(seed), .base = base, .grid_total = grid, .total = grid + if (heavy) tries_heavy else tries };
}
/// Starts the next vector; false when the budget is spent.
pub fn next(self: *Source) bool {
if (self.step >= self.total) return false;
self.step += 1;
self.slot = 0;
begin();
return true;
}
/// The next free variable's value, within lo..hi, or null if no value of this vector fits.
pub fn pick(self: *Source, lo: i128, hi: i128) ?i128 {
const s = self.slot;
self.slot += 1;
if (self.step <= self.grid_total) {
var idx = self.step - 1;
for (0..s) |_| idx /= self.base;
const v = @max(lo, -@as(i128, self.base / 2)) + @as(i128, idx % self.base);
return if (v > hi) null else v;
}
return self.rng.pick(lo, hi);
}
};
/// Collects up to 16 distinct admitted vectors, to check a theorem was exercised.
pub fn Tally(comptime n: usize) type {
return struct {
seen: [16][n]i128 = undefined,
count: usize = 0,
const Self = @This();
pub fn init() Self {
skip_count = 0;
return .{};
}
pub fn record(self: *Self, v: [n]i128) void {
if (self.count == 16) return;
for (self.seen[0..self.count]) |s| {
if (std.mem.eql(i128, &s, &v)) return;
}
self.seen[self.count] = v;
self.count += 1;
}
/// Counts the vector unless it was skipped (overflow or undecided search); fails when the conclusion is false.
pub fn admit(self: *Self, ok: bool, v: [n]i128) error{TestUnexpectedResult}!void {
if (skipped()) return;
self.record(v);
if (!ok) return error.TestUnexpectedResult;
}
/// At least k distinct vectors were admitted. NoVector: none was, TooFewVectors: some, OnlySkipped: skips (overflow or
/// an undecided search) outnumbered admissions.
pub fn require(self: *const Self, k: usize) error{ TooFewVectors, NoVector, OnlySkipped }!void {
if (self.count >= k) return;
if (skip_count > 0 and skip_count >= self.count) return error.OnlySkipped;
if (self.count == 0) return error.NoVector;
return error.TooFewVectors;
}
};
}