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Fix is_partial_transformation #67

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b0d4e87
Fix is_partial_transformation
james-d-mitchell Nov 19, 2025
826446a
Adjust is_partial_transformation tests in test_epu8
james-d-mitchell Nov 19, 2025
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30 changes: 25 additions & 5 deletions include/hpcombi/epu8_impl.hpp
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Original file line number Diff line number Diff line change
Expand Up @@ -52,6 +52,27 @@

namespace HPCombi {

static constexpr const std::array<epu8, 17> MASK =
{
Epu8(0),
{0xFF, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0},
{0xFF, 0xFF, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0},
{0xFF, 0xFF, 0xFF, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0},
{0xFF, 0xFF, 0xFF, 0xFF, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0},
{0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0},
{0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0},
{0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0, 0, 0, 0, 0, 0, 0, 0, 0},
{0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0, 0, 0, 0, 0, 0, 0, 0},
{0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0, 0, 0, 0, 0, 0, 0},
{0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0, 0, 0, 0, 0, 0},
{0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0, 0, 0, 0, 0},
{0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0, 0, 0, 0},
{0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0, 0, 0},
{0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0, 0},
{0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0},
Epu8(0xFF)
};

///////////////////////////////////////////////////////////////////////////////
// Implementation part for inline functions
///////////////////////////////////////////////////////////////////////////////
Expand Down Expand Up @@ -483,12 +504,11 @@ inline epu8 popcount16(epu8 v) noexcept {
permuted(Epu8.popcount(), v >> 4));
}



inline bool is_partial_transformation(epu8 v, const size_t k) noexcept {
uint64_t diff = last_diff(v, Epu8.id(), 16);
// (forall x in v, x + 1 <= 16) and
// (v = Perm16::one() or last diff index < 16)
return (simde_mm_movemask_epi8(v + Epu8(1) <= Epu8(0x10)) == 0xffff) &&
(diff == 16 || diff < k);
HPCOMBI_ASSERT(k <= 16);
return simde_mm_movemask_epi8((v & MASK[k]) + Epu8(1) <= Epu8(0x10)) == 0xffff;
}

inline bool is_transformation(epu8 v, const size_t k) noexcept {
Expand Down
10 changes: 5 additions & 5 deletions tests/test_epu8.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -648,17 +648,17 @@ TEST_CASE_METHOD(Fix, "is_partial_transformation", "[Epu8][063]") {
CHECK(is_partial_transformation(Epu8({}, 0xff)));
CHECK(is_partial_transformation(Epu8({2, 0xff, 3}, 0)));

CHECK(!is_partial_transformation(zero, 15));
CHECK(is_partial_transformation(zero, 15));
CHECK(is_partial_transformation(Pa));
CHECK(is_partial_transformation(Pa, 6));
CHECK(is_partial_transformation(Pa, 5));
CHECK(!is_partial_transformation(Pa, 4));
CHECK(!is_partial_transformation(Pa, 1));
CHECK(!is_partial_transformation(Pa, 0));
CHECK(is_partial_transformation(Pa, 4));
CHECK(is_partial_transformation(Pa, 1));
CHECK(is_partial_transformation(Pa, 0));

CHECK(is_partial_transformation(RP));
CHECK(is_partial_transformation(RP, 16));
CHECK(!is_partial_transformation(RP, 15));
CHECK(is_partial_transformation(RP, 15));
CHECK(is_partial_transformation(Epu8({1, 2, 1, 0xFF, 0, 5, 0xFF, 2}, 0)));
CHECK(!is_partial_transformation(Epu8({1, 2, 1, 0xFF, 0, 16, 0xFF, 2}, 0)));
}
Expand Down
28 changes: 28 additions & 0 deletions tests/test_perm16.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -535,4 +535,32 @@ TEST_CASE_METHOD(Perm16Fixture, "Perm16::left_weak_leq", "[Perm16][044]") {
}
}
}

TEST_CASE("PTransf16::validate", "[PTransf16][045]") {
PTransf16 x({0, 1, 255});
REQUIRE(x.validate(16));
REQUIRE(x.validate(2));
REQUIRE(x.validate(3));

x = PTransf16({0, 1});
REQUIRE(x.validate(16));
REQUIRE(x.validate(2));
REQUIRE(x.validate(3));

x = PTransf16({1, 0});
REQUIRE(x.validate(16));
REQUIRE(x.validate(2));
REQUIRE(x.validate(3));

x = PTransf16({0xFF, 0});
REQUIRE(x.validate(16));
REQUIRE(x.validate(1));
REQUIRE(x.validate(2));
REQUIRE(x.validate(3));

x = PTransf16({0, 1, 2, 17});
REQUIRE(x.validate(3));
REQUIRE(!x.validate(4));
REQUIRE(!x.validate());
}
} // namespace HPCombi