def hd_of

bend-collections-laws-math@1.0.0.0 · proofs/math/random/uint64n.bend:182

import Base
import bend-collections-laws-math@1.0.0.0/spec/lib/common.bend as C
import bend-collections-laws-math@1.0.0.0/spec/math/w64.bend as SW
import bend-collections-laws-math@1.0.0.0/spec/math/random/rand.bend as SR
import bend-collections-laws-math@1.0.0.0/src/math/u64.bend as WU
import bend-collections-laws-math@1.0.0.0/src/math/w64.bend as X

182def hd_of(+x: WU.U64, +n: WU.U64, +m: Nat, +t: WU.U64, +hv: {SW.value(n) == 1n+m : Nat}, +hp: {Nat.is_eq(SR.and_bits(64n, 1n+m, m), 0n) == False{} : Bool}, +htn: {Nat.is_lt(SR.pow2mod(64n, 1n+m), 1n+m) == True{} : Bool}, +ht: {SW.value(t) == SR.pow2mod(64n, 1n+m) : Nat}, +c: Bool, +hc: {X.lt(X.pfst(X.mul128(x, n)), t) == c : Bool}) -> {SR.draw(64n, SW.value(x), 1n+m) == SR.accept(C.high(64n, Nat.mul(SW.value(x), 1n+m)), Bool.not(c)) : Maybe<&2, Nat>}:
183  dec(SW.value(x), m, hp, htn, c, Equal.trans(Bool, Nat.is_lt(C.low(64n, Nat.mul(SW.value(x), 1n+m)), SR.pow2mod(64n, 1n+m)), X.lt(X.pfst(X.mul128(x, n)), t), c, Equal.sym(Bool, X.lt(X.pfst(X.mul128(x, n)), t), Nat.is_lt(C.low(64n, Nat.mul(SW.value(x), 1n+m)), SR.pow2mod(64n, 1n+m)), lt_low(x, n, m, t, hv, ht)), hc))