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Merged
yspolyakov merged 1 commit into from
May 18, 2026
Merged

Optimizations for KeySwitchCore/EvalFastRotation #1187

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134 changes: 48 additions & 86 deletions benchmark/src/lib-benchmark.cpp
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15 changes: 7 additions & 8 deletions src/pke/include/keyswitch/keyswitch-base.h
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Original file line number Diff line number Diff line change
Expand Up @@ -113,8 +113,7 @@ class KeySwitchBase {
// CORE OPERATIONS
/////////////////////////////////////////

virtual std::shared_ptr<std::vector<Element>> KeySwitchCore(const Element& a,
const EvalKey<Element> evalKey) const {
virtual std::vector<Element> KeySwitchCore(const Element& a, const EvalKey<Element> evalKey) const {
OPENFHE_THROW(NOT_SUPPORTED_ERROR);
}

Expand All @@ -123,15 +122,15 @@ class KeySwitchBase {
OPENFHE_THROW(NOT_SUPPORTED_ERROR);
}

virtual std::shared_ptr<std::vector<Element>> EvalFastKeySwitchCore(
const std::shared_ptr<std::vector<Element>> digits, const EvalKey<Element> evalKey,
const std::shared_ptr<ParmType> paramsQl) const {
virtual std::vector<Element> EvalFastKeySwitchCore(const std::shared_ptr<std::vector<Element>> digits,
const EvalKey<Element> evalKey,
const std::shared_ptr<ParmType> paramsQl) const {
OPENFHE_THROW(NOT_SUPPORTED_ERROR);
}

virtual std::shared_ptr<std::vector<Element>> EvalFastKeySwitchCoreExt(
const std::shared_ptr<std::vector<Element>> digits, const EvalKey<Element> evalKey,
const std::shared_ptr<ParmType> paramsQl) const {
virtual std::vector<Element> EvalFastKeySwitchCoreExt(const std::shared_ptr<std::vector<Element>> digits,
const EvalKey<Element> evalKey,
const std::shared_ptr<ParmType> paramsQl) const {
OPENFHE_THROW(NOT_SUPPORTED_ERROR);
}
};
Expand Down
9 changes: 4 additions & 5 deletions src/pke/include/keyswitch/keyswitch-bv.h
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Expand Up @@ -80,15 +80,14 @@ class KeySwitchBV : public KeySwitchRNS {
// CORE OPERATIONS
/////////////////////////////////////////

std::shared_ptr<std::vector<DCRTPoly>> KeySwitchCore(const DCRTPoly& a,
const EvalKey<DCRTPoly> evalKey) const override;
std::vector<DCRTPoly> KeySwitchCore(const DCRTPoly& a, const EvalKey<DCRTPoly> evalKey) const override;

std::shared_ptr<std::vector<DCRTPoly>> EvalKeySwitchPrecomputeCore(
const DCRTPoly& c, std::shared_ptr<CryptoParametersBase<DCRTPoly>> cryptoParamsBase) const override;

std::shared_ptr<std::vector<DCRTPoly>> EvalFastKeySwitchCore(
const std::shared_ptr<std::vector<DCRTPoly>> digits, const EvalKey<DCRTPoly> evalKey,
const std::shared_ptr<ParmType> paramsQl) const override;
std::vector<DCRTPoly> EvalFastKeySwitchCore(const std::shared_ptr<std::vector<DCRTPoly>> digits,
const EvalKey<DCRTPoly> evalKey,
const std::shared_ptr<ParmType> paramsQl) const override;

/////////////////////////////////////////
// SERIALIZATION
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15 changes: 7 additions & 8 deletions src/pke/include/keyswitch/keyswitch-hybrid.h
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Expand Up @@ -94,19 +94,18 @@ class KeySwitchHYBRID : public KeySwitchRNS {
// CORE OPERATIONS
/////////////////////////////////////////

std::shared_ptr<std::vector<DCRTPoly>> KeySwitchCore(const DCRTPoly& a,
const EvalKey<DCRTPoly> evalKey) const override;
std::vector<DCRTPoly> KeySwitchCore(const DCRTPoly& a, const EvalKey<DCRTPoly> evalKey) const override;

std::shared_ptr<std::vector<DCRTPoly>> EvalKeySwitchPrecomputeCore(
const DCRTPoly& c, std::shared_ptr<CryptoParametersBase<DCRTPoly>> cryptoParamsBase) const override;

std::shared_ptr<std::vector<DCRTPoly>> EvalFastKeySwitchCore(
const std::shared_ptr<std::vector<DCRTPoly>> digits, const EvalKey<DCRTPoly> evalKey,
const std::shared_ptr<ParmType> paramsQl) const override;
std::vector<DCRTPoly> EvalFastKeySwitchCore(const std::shared_ptr<std::vector<DCRTPoly>> digits,
const EvalKey<DCRTPoly> evalKey,
const std::shared_ptr<ParmType> paramsQl) const override;

std::shared_ptr<std::vector<DCRTPoly>> EvalFastKeySwitchCoreExt(
const std::shared_ptr<std::vector<DCRTPoly>> digits, const EvalKey<DCRTPoly> evalKey,
const std::shared_ptr<ParmType> paramsQl) const override;
std::vector<DCRTPoly> EvalFastKeySwitchCoreExt(const std::shared_ptr<std::vector<DCRTPoly>> digits,
const EvalKey<DCRTPoly> evalKey,
const std::shared_ptr<ParmType> paramsQl) const override;

/////////////////////////////////////////
// SERIALIZATION
Expand Down
15 changes: 7 additions & 8 deletions src/pke/include/schemebase/base-scheme.h
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Expand Up @@ -291,9 +291,9 @@ class SchemeBase {
return m_KeySwitch->EvalKeySwitchPrecomputeCore(c, cryptoParamsBase);
}

virtual std::shared_ptr<std::vector<Element>> EvalFastKeySwitchCoreExt(
const std::shared_ptr<std::vector<Element>> digits, const EvalKey<Element> evalKey,
const std::shared_ptr<ParmType> params) const {
virtual std::vector<Element> EvalFastKeySwitchCoreExt(const std::shared_ptr<std::vector<Element>> digits,
const EvalKey<Element> evalKey,
const std::shared_ptr<ParmType> params) const {
VerifyKeySwitchEnabled(__func__);
if (nullptr == digits)
OPENFHE_THROW("Input digits is nullptr");
Expand All @@ -306,9 +306,9 @@ class SchemeBase {
return m_KeySwitch->EvalFastKeySwitchCoreExt(digits, evalKey, params);
}

virtual std::shared_ptr<std::vector<Element>> EvalFastKeySwitchCore(
const std::shared_ptr<std::vector<Element>> digits, const EvalKey<Element> evalKey,
const std::shared_ptr<ParmType> params) const {
virtual std::vector<Element> EvalFastKeySwitchCore(const std::shared_ptr<std::vector<Element>> digits,
const EvalKey<Element> evalKey,
const std::shared_ptr<ParmType> params) const {
VerifyKeySwitchEnabled(__func__);
if (nullptr == digits)
OPENFHE_THROW("Input digits is nullptr");
Expand All @@ -321,8 +321,7 @@ class SchemeBase {
return m_KeySwitch->EvalFastKeySwitchCore(digits, evalKey, params);
}

virtual std::shared_ptr<std::vector<Element>> KeySwitchCore(const Element& a,
const EvalKey<Element> evalKey) const {
virtual std::vector<Element> KeySwitchCore(const Element& a, const EvalKey<Element> evalKey) const {
VerifyKeySwitchEnabled(__func__);
if (!evalKey)
OPENFHE_THROW("Input evaluation key is nullptr");
Expand Down
29 changes: 13 additions & 16 deletions src/pke/lib/keyswitch/keyswitch-bv.cpp
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Expand Up @@ -227,23 +227,19 @@ EvalKey<DCRTPoly> KeySwitchBV::KeySwitchGenInternal(const PrivateKey<DCRTPoly> o
void KeySwitchBV::KeySwitchInPlace(Ciphertext<DCRTPoly>& ciphertext, const EvalKey<DCRTPoly> ek) const {
auto& cv = ciphertext->GetElements();
auto ba = KeySwitchCore(cv.back(), ek);

cv[0].SetFormat(Format::EVALUATION);
cv[0] += (*ba)[0];

cv[0] += ba[0];
if (cv.size() > 2) {
cv[1].SetFormat(Format::EVALUATION);
cv[1] += (*ba)[1];
cv[1] += ba[1];
}
else {
cv[1] = (*ba)[1];
cv[1] = ba[1];
}

cv.resize(2);
}

std::shared_ptr<std::vector<DCRTPoly>> KeySwitchBV::KeySwitchCore(const DCRTPoly& a,
const EvalKey<DCRTPoly> evalKey) const {
std::vector<DCRTPoly> KeySwitchBV::KeySwitchCore(const DCRTPoly& a, const EvalKey<DCRTPoly> evalKey) const {
return EvalFastKeySwitchCore(EvalKeySwitchPrecomputeCore(a, evalKey->GetCryptoParameters()), evalKey,
a.GetParams());
}
Expand All @@ -254,9 +250,9 @@ std::shared_ptr<std::vector<DCRTPoly>> KeySwitchBV::EvalKeySwitchPrecomputeCore(
return std::make_shared<std::vector<DCRTPoly>>(c.CRTDecompose(cryptoParams->GetDigitSize()));
}

std::shared_ptr<std::vector<DCRTPoly>> KeySwitchBV::EvalFastKeySwitchCore(
const std::shared_ptr<std::vector<DCRTPoly>> digits, const EvalKey<DCRTPoly> evalKey,
const std::shared_ptr<ParmType> paramsQl) const {
std::vector<DCRTPoly> KeySwitchBV::EvalFastKeySwitchCore(const std::shared_ptr<std::vector<DCRTPoly>> digits,
const EvalKey<DCRTPoly> evalKey,
const std::shared_ptr<ParmType> paramsQl) const {
std::vector<DCRTPoly> bv(evalKey->GetBVector());
std::vector<DCRTPoly> av(evalKey->GetAVector());
const auto diffQl = bv[0].GetParams()->GetParams().size() - paramsQl->GetParams().size();
Expand All @@ -268,13 +264,14 @@ std::shared_ptr<std::vector<DCRTPoly>> KeySwitchBV::EvalFastKeySwitchCore(
av[i].DropLastElements(diffQl);
av[i] *= (*digits)[i];
}

std::vector<DCRTPoly> res{std::move(bv[0]), std::move(av[0])};
for (uint32_t i = 1; i < limit; ++i) {
res[0] += bv[i];
res[1] += av[i];
bv[0] += bv[i];
av[0] += av[i];
}
return std::make_shared<std::vector<DCRTPoly>>(std::move(res));
std::vector<DCRTPoly> res;
res.emplace_back(std::move(bv[0]));
res.emplace_back(std::move(av[0]));
return res;
}

} // namespace lbcrypto
58 changes: 26 additions & 32 deletions src/pke/lib/keyswitch/keyswitch-hybrid.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -199,18 +199,15 @@ EvalKey<DCRTPoly> KeySwitchHYBRID::KeySwitchGenInternal(const PrivateKey<DCRTPol
void KeySwitchHYBRID::KeySwitchInPlace(Ciphertext<DCRTPoly>& ciphertext, const EvalKey<DCRTPoly> ek) const {
auto& cv = ciphertext->GetElements();
auto ba = KeySwitchCore(cv.back(), ek);

cv[0].SetFormat(Format::EVALUATION);
cv[0] += (*ba)[0];

cv[0] += ba[0];
if (cv.size() > 2) {
cv[1].SetFormat(Format::EVALUATION);
cv[1] += (*ba)[1];
cv[1] += ba[1];
}
else {
cv[1] = (*ba)[1];
cv[1] = ba[1];
}

cv.resize(2);
}

Expand Down Expand Up @@ -305,8 +302,7 @@ DCRTPoly KeySwitchHYBRID::KeySwitchDownFirstElement(ConstCiphertext<DCRTPoly> ci
cryptoParams->GettInvModpPrecon(), t, cryptoParams->GettModqPrecon());
}

std::shared_ptr<std::vector<DCRTPoly>> KeySwitchHYBRID::KeySwitchCore(const DCRTPoly& a,
const EvalKey<DCRTPoly> evalKey) const {
std::vector<DCRTPoly> KeySwitchHYBRID::KeySwitchCore(const DCRTPoly& a, const EvalKey<DCRTPoly> evalKey) const {
return EvalFastKeySwitchCore(EvalKeySwitchPrecomputeCore(a, evalKey->GetCryptoParameters()), evalKey,
a.GetParams());
}
Expand Down Expand Up @@ -378,30 +374,30 @@ std::shared_ptr<std::vector<DCRTPoly>> KeySwitchHYBRID::EvalKeySwitchPrecomputeC
return result;
}

std::shared_ptr<std::vector<DCRTPoly>> KeySwitchHYBRID::EvalFastKeySwitchCore(
const std::shared_ptr<std::vector<DCRTPoly>> digits, const EvalKey<DCRTPoly> evalKey,
const std::shared_ptr<ParmType> paramsQl) const {
std::vector<DCRTPoly> KeySwitchHYBRID::EvalFastKeySwitchCore(const std::shared_ptr<std::vector<DCRTPoly>> digits,
const EvalKey<DCRTPoly> evalKey,
const std::shared_ptr<ParmType> paramsQl) const {
const auto cryptoParams = std::dynamic_pointer_cast<CryptoParametersRNS>(evalKey->GetCryptoParameters());

const PlaintextModulus t = (cryptoParams->GetNoiseScale() == 1) ? 0 : cryptoParams->GetPlaintextModulus();

auto result = EvalFastKeySwitchCoreExt(digits, evalKey, paramsQl);
(*result)[0] = (*result)[0].ApproxModDown(paramsQl, cryptoParams->GetParamsP(), cryptoParams->GetPInvModq(),
cryptoParams->GetPInvModqPrecon(), cryptoParams->GetPHatInvModp(),
cryptoParams->GetPHatInvModpPrecon(), cryptoParams->GetPHatModq(),
cryptoParams->GetModqBarrettMu(), cryptoParams->GettInvModp(),
cryptoParams->GettInvModpPrecon(), t, cryptoParams->GettModqPrecon());
(*result)[1] = (*result)[1].ApproxModDown(paramsQl, cryptoParams->GetParamsP(), cryptoParams->GetPInvModq(),
cryptoParams->GetPInvModqPrecon(), cryptoParams->GetPHatInvModp(),
cryptoParams->GetPHatInvModpPrecon(), cryptoParams->GetPHatModq(),
cryptoParams->GetModqBarrettMu(), cryptoParams->GettInvModp(),
cryptoParams->GettInvModpPrecon(), t, cryptoParams->GettModqPrecon());
auto result = EvalFastKeySwitchCoreExt(digits, evalKey, paramsQl);
result[0] = result[0].ApproxModDown(paramsQl, cryptoParams->GetParamsP(), cryptoParams->GetPInvModq(),
cryptoParams->GetPInvModqPrecon(), cryptoParams->GetPHatInvModp(),
cryptoParams->GetPHatInvModpPrecon(), cryptoParams->GetPHatModq(),
cryptoParams->GetModqBarrettMu(), cryptoParams->GettInvModp(),
cryptoParams->GettInvModpPrecon(), t, cryptoParams->GettModqPrecon());
result[1] = result[1].ApproxModDown(paramsQl, cryptoParams->GetParamsP(), cryptoParams->GetPInvModq(),
cryptoParams->GetPInvModqPrecon(), cryptoParams->GetPHatInvModp(),
cryptoParams->GetPHatInvModpPrecon(), cryptoParams->GetPHatModq(),
cryptoParams->GetModqBarrettMu(), cryptoParams->GettInvModp(),
cryptoParams->GettInvModpPrecon(), t, cryptoParams->GettModqPrecon());
return result;
}

std::shared_ptr<std::vector<DCRTPoly>> KeySwitchHYBRID::EvalFastKeySwitchCoreExt(
const std::shared_ptr<std::vector<DCRTPoly>> digits, const EvalKey<DCRTPoly> evalKey,
const std::shared_ptr<ParmType> paramsQl) const {
std::vector<DCRTPoly> KeySwitchHYBRID::EvalFastKeySwitchCoreExt(const std::shared_ptr<std::vector<DCRTPoly>> digits,
const EvalKey<DCRTPoly> evalKey,
const std::shared_ptr<ParmType> paramsQl) const {
const auto paramsQlP = (*digits)[0].GetParams();
const uint32_t sizeQlP = paramsQlP->GetParams().size();

Expand All @@ -413,11 +409,9 @@ std::shared_ptr<std::vector<DCRTPoly>> KeySwitchHYBRID::EvalFastKeySwitchCoreExt
const auto& av = evalKey->GetAVector();
const auto& bv = evalKey->GetBVector();

auto result = std::make_shared<std::vector<DCRTPoly>>();
result->reserve(2);
result->emplace_back(paramsQlP, Format::EVALUATION, true);
result->emplace_back(paramsQlP, Format::EVALUATION, true);
auto& elements = (*result);
std::vector<DCRTPoly> result;
result.emplace_back(paramsQlP, Format::EVALUATION, true);
result.emplace_back(paramsQlP, Format::EVALUATION, true);

for (uint32_t j = 0; j < limit; ++j) {
#pragma omp parallel for num_threads(OpenFHEParallelControls.GetThreadLimit(sizeQlP))
Expand All @@ -426,8 +420,8 @@ std::shared_ptr<std::vector<DCRTPoly>> KeySwitchHYBRID::EvalFastKeySwitchCoreExt
const auto& cji = (*digits)[j].GetElementAtIndex(i);
const auto& bji = bv[j].GetElementAtIndex(idx);
const auto& aji = av[j].GetElementAtIndex(idx);
elements[0].SetElementAtIndex(i, elements[0].GetElementAtIndex(i) + cji * bji);
elements[1].SetElementAtIndex(i, elements[1].GetElementAtIndex(i) + cji * aji);
result[0].SetElementAtIndex(i, result[0].GetElementAtIndex(i) + cji * bji);
result[1].SetElementAtIndex(i, result[1].GetElementAtIndex(i) + cji * aji);
}
}

Expand Down
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