Add reverse-mode constraint-propagation functions#756
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Move reverse-mode elementary functions, previously in IntervalContractors.jl,
into the core package as `src/intervals/interval_operations/reverse.jl`:
- §10.5.4 reverses: `sqr_rev`, `abs_rev`, `pown_rev`, `sin_rev`, `cos_rev`,
`tan_rev`, `cosh_rev`, `mul_rev`
- Additional reverses: `add_rev`, `sub_rev{1,2}`, `div_rev{1,2}`,
`sqrt_rev`, `cbrt_rev`, `exp{,2,10}_rev`, `expm1_rev`,
`log{,2,10}_rev`, `log1p_rev`, `sinh_rev`, `tanh_rev`,
`asin_rev`, `acos_rev`, `atan_rev`, `asinh_rev`, `acosh_rev`, `atanh_rev`
Decorated `Interval` outputs are forced to `trv` per §11.7.1; NaI inputs
propagate to NaI.
Includes the libieeep1788 ITF1788 reverse test corpus and a `reverse.jl`
unit-test file. Test generator extended with reverse-function dispatch
entries and a `_mul_rev_to_pair` helper for the `mulRevToPair` cases.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Port the additional reverse-mode functions previously living in
IntervalContractors.jl that are not collisions with existing IA APIs:
- `mul_rev_to_pair` — IEEE 1788-2015 §10.5.5 two-output reverse
multiplication, returning the disjoint half-rays when `0 ∈ b`.
Decoration follows §11.7.1: `trv` on a true split, otherwise the
standard division decoration on the first output.
- `inv_rev` — reverse of `inv`; inv is its own inverse.
- `sign_rev` — reverse of `sign`; preimage assembled from which of
`{-1, 0, 1}` lies in the constraint.
- `pow_rev1(b, c)` — reverse of `^` in the base, `c^(1/b) ∩ x`.
- `pow_rev2(a, c)` — reverse of `^` in the exponent,
`(log(c) / log(a)) ∩ x`.
All five functions follow the existing `BareInterval` impl + `Interval`
dispatch via `_rev_dispatch` pattern, with §11.7.1 `trv` decoration on
single-output Interval results. New unit tests in
`test/interval_tests/reverse.jl` cover NaI propagation, decoration,
empty/entire edge cases, and the §10.5.5 split behaviour for
`mul_rev_to_pair`.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
…, power_rev, max_rev, min_rev) Port the constraint-propagation-style tuple-rewriting reverses from IntervalContractors.jl. Given a binary forward `a = f(b, c)`, each function returns the triplet `(a, b', c')` where `b' ⊆ b`, `c' ⊆ c` are the tightenings induced by the constraint and `a` is unchanged. Names and arities preserved from IntervalContractors except `mul_rev`, which is renamed `times_rev` because IA already exports a same-arity `mul_rev(b, c, x)` with the IEEE 1788 §10.5.4 single-output semantics. Methods added: - `plus_rev(a, b, c)` — `a = b + c` - `minus_rev(a, b, c)` — `a = b - c` - `minus_rev(a, b)` — `a = -b` - `times_rev(a, b, c)` — `a = b * c` (was `mul_rev` in IC) - `div_rev(a, b, c)` — `a = b / c` - `power_rev(a, b, n::Integer)` — `a = b^n`, integer exponent - `power_rev(a, n::Integer)` — defaults `b = entireinterval()` - `power_rev(a, b, c)` — `a = b^c`, interval exponent - `max_rev(a, b, c)`, `min_rev` — `a = max(b, c)` / `min(b, c)` Implementation notes: - Adds a `_rev_dispatch_tuple` helper bridging `BareInterval` impls to the `Interval` API: NaI propagation across the whole tuple, `trv` decoration on derived outputs (per §11.7.1) while passing through unchanged inputs with their original decorations. - `power_rev` uses IA's existing `rootn`, which already handles negative exponents (`inv(rootn(·, |n|))`) and even-`n` clipping to `[0, ∞)`. - `times_rev` uses `extended_div` + hull when `0 ∈ b` or `0 ∈ c` to deliver a single-interval enclosure of each output. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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Reflects the new reverse-mode constraint-propagation API added in this branch. `IntervalContractors.jl`'s deprecation PR pins `IntervalArithmetic = "1.1"` to ensure callers see the new exports. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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Summary
Adds reverse-mode elementary functions for interval constraint propagation, previously living in
IntervalContractors.jl, into the core package. This is the IA half of the planned move; a companionIntervalContractors.jldeprecation PR will follow.Three commits, building cleanly on top of master:
sqr_rev,abs_rev,pown_rev,sin_rev,cos_rev,tan_rev,cosh_rev,mul_rev) plus the standard additional reverses from the constraint-propagation literature (add_rev,sub_rev1/2,div_rev1/2,sqrt_rev,cbrt_rev, theexp{,2,10}/expm1family, thelog{,2,10}/log1pfamily,sinh/tanh/asinh/atanh, andasin/acos/atan). Includes thelibieeep1788_rev.itlandlibieeep1788_mul_rev.itlITF1788 test corpora.mul_rev_to_pair,inv_rev,sign_rev,pow_rev1,pow_rev2.mul_rev_to_pairfollows §11.7.1 decoration (trvon a true split, propagated standard-division decoration otherwise).plus_rev(a, b, c),minus_rev(3-arg + unary),times_rev,div_rev,power_rev(Integer + Interval forms),max_rev,min_rev. These return(a, b', c')withapassed through andb'/c'decoratedtrvper §11.7.1. Note: the IntervalContractors namemul_revis renamed totimes_revhere to avoid colliding with the IEEE 1788 single-outputmul_rev(b, c, x)already added in commit (1).API design:
Intervalmethods accept an optionaldec = :defaultkwarg and forcetrvper §11.7.1.Intervalmethods use a_rev_dispatch_tuplehelper that propagates NaI across the whole tuple and decorates only the derived outputs astrv(input passthroughs keep their original decoration).power_revreuses IA's existingrootn(which already handles even-nclipping and negativenviainv(rootn(·, |n|))).Test plan
test/interval_tests/reverse.jl: 127/127 unit tests covering NaI propagation, decoration, empty/entire edge cases, and the §10.5.5 split behaviour formul_rev_to_pair.test/ITF1788_tests/libieeep1788_rev.jl+libieeep1788_mul_rev.jl: 1123/1127 (4 known-loose@test_broken).ReversePropagation.jlandIntervalConstraintProgramming.jlalready call IA's IEEE 1788 reverses; this PR is what unblocks them.🤖 Generated with Claude Code