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Added complex scalar addition and complex scalar multiplication, with further testing, found that scalar addition with negative numbers doesn't work. #18

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7 changes: 7 additions & 0 deletions api/CCParams.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -87,6 +87,13 @@ void CCParams<CryptoContextCKKSRNS>::SetSecurityLevel(SecurityLevel level) {
params.SetSecurityLevel(sl_openfhe);
}

void CCParams<CryptoContextCKKSRNS>::SetCKKSDataType(CKKSDataType ckksdt) {
auto& params = std::any_cast<lbcrypto::CCParams<lbcrypto::CryptoContextCKKSRNS>&>(cpu);
auto dt_openfhe = static_cast<lbcrypto::CKKSDataType>(ckksdt);
assert((int)dt_openfhe == (int)ckksdt);
params.SetCKKSDataType(dt_openfhe);
}

// ---- Getters ----

SecretKeyDist CCParams<CryptoContextCKKSRNS>::GetSecretKeyDist() const {
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1 change: 1 addition & 0 deletions api/CCParams.hpp
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Expand Up @@ -49,6 +49,7 @@ template <> class CCParams<CryptoContextCKKSRNS> {
void SetDevices(std::vector<int>&& devices);
void SetPlaintextAutoload(bool autoload);
void SetCiphertextAutoload(bool autoload);
void SetCKKSDataType(CKKSDataType ckksdt);

// ---- Getters ----
SecretKeyDist GetSecretKeyDist() const;
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97 changes: 97 additions & 0 deletions api/CryptoContext.cpp
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Expand Up @@ -747,6 +747,32 @@ Ciphertext<DCRTPoly> CryptoContextImpl<DCRTPoly>::EvalAdd(double scalar, const C
return EvalAdd(ct, scalar);
}

Ciphertext<DCRTPoly> CryptoContextImpl<DCRTPoly>::EvalAdd(const Ciphertext<DCRTPoly>& ct, std::complex<double> scalar) {

// Fall back to CPU.
if (this->devices.empty()) {
auto& context = std::any_cast<const lbcrypto::CryptoContext<lbcrypto::DCRTPoly>&>(this->cpu);
auto& ctImpl = std::any_cast<const lbcrypto::Ciphertext<lbcrypto::DCRTPoly>&>(ct->cpu);
auto ct = context->EvalAdd(ctImpl, scalar);
Ciphertext<DCRTPoly> ciphertext = std::make_shared<CiphertextImpl<DCRTPoly>>(this->self_reference.lock());
ciphertext->cpu = std::make_any<lbcrypto::Ciphertext<lbcrypto::DCRTPoly>>(ct);
return ciphertext;
}

// GPU path.
this->LoadCiphertext(const_cast<Ciphertext<DCRTPoly>&>(ct));

Ciphertext<DCRTPoly> result = std::make_shared<CiphertextImpl<DCRTPoly>>(*ct);
auto res_gpu = std::static_pointer_cast<FIDESlib::CKKS::Ciphertext>(this->GetDeviceCiphertext(result->gpu));
res_gpu->addScalar(scalar);

return result;
}

Ciphertext<DCRTPoly> CryptoContextImpl<DCRTPoly>::EvalAdd(std::complex<double> scalar, const Ciphertext<DCRTPoly>& ct) {
return EvalAdd(ct, scalar);
}

void CryptoContextImpl<DCRTPoly>::EvalAddInPlace(Ciphertext<DCRTPoly>& ct1, const Ciphertext<DCRTPoly>& ct2) {

// Fall back to CPU.
Expand Down Expand Up @@ -815,6 +841,28 @@ void CryptoContextImpl<DCRTPoly>::EvalAddInPlace(double scalar, Ciphertext<DCRTP
EvalAddInPlace(ct1, scalar);
}

void CryptoContextImpl<DCRTPoly>::EvalAddInPlace(Ciphertext<DCRTPoly>& ct1, std::complex<double> scalar) {

// Fall back to CPU.
if (this->devices.empty()) {

auto& context = std::any_cast<const lbcrypto::CryptoContext<lbcrypto::DCRTPoly>&>(this->cpu);
auto& ct1Impl = std::any_cast<lbcrypto::Ciphertext<lbcrypto::DCRTPoly>&>(ct1->cpu);
context->EvalAddInPlace(ct1Impl, scalar);
return;
}

// GPU path.
this->LoadCiphertext(ct1);

auto res_gpu = std::static_pointer_cast<FIDESlib::CKKS::Ciphertext>(this->GetDeviceCiphertext(ct1->gpu));
res_gpu->addScalar(scalar);
}

void CryptoContextImpl<DCRTPoly>::EvalAddInPlace(std::complex<double> scalar, Ciphertext<DCRTPoly>& ct1) {
EvalAddInPlace(ct1, scalar);
}

Ciphertext<DCRTPoly> CryptoContextImpl<DCRTPoly>::EvalAddMutable(Ciphertext<DCRTPoly>& ct1, Ciphertext<DCRTPoly>& ct2) {
return EvalAdd(ct1, ct2);
}
Expand Down Expand Up @@ -1198,6 +1246,33 @@ Ciphertext<DCRTPoly> CryptoContextImpl<DCRTPoly>::EvalMult(double scalar, const
return EvalMult(ct1, scalar);
}

Ciphertext<DCRTPoly> CryptoContextImpl<DCRTPoly>::EvalMult(const Ciphertext<DCRTPoly>& ct1, std::complex<double> scalar) {

// Fall back to CPU.
if (this->devices.empty()) {

auto& context = std::any_cast<const lbcrypto::CryptoContext<lbcrypto::DCRTPoly>&>(this->cpu);
auto& ct1Impl = std::any_cast<const lbcrypto::Ciphertext<lbcrypto::DCRTPoly>&>(ct1->cpu);
auto ct = context->EvalMult(ct1Impl, scalar);
Ciphertext<DCRTPoly> ciphertext = std::make_shared<CiphertextImpl<DCRTPoly>>(this->self_reference.lock());
ciphertext->cpu = std::make_any<lbcrypto::Ciphertext<lbcrypto::DCRTPoly>>(ct);
return ciphertext;
}

// GPU path.
this->LoadCiphertext(const_cast<Ciphertext<DCRTPoly>&>(ct1));

Ciphertext<DCRTPoly> result = std::make_shared<CiphertextImpl<DCRTPoly>>(*ct1);
auto res_gpu = std::static_pointer_cast<FIDESlib::CKKS::Ciphertext>(this->GetDeviceCiphertext(result->gpu));
res_gpu->multScalar(scalar);

return result;
}

Ciphertext<DCRTPoly> CryptoContextImpl<DCRTPoly>::EvalMult(std::complex<double> scalar, const Ciphertext<DCRTPoly>& ct1) {
return EvalMult(ct1, scalar);
}

void CryptoContextImpl<DCRTPoly>::EvalMultInPlace(Ciphertext<DCRTPoly>& ct1, Plaintext& pt) {

if (this->devices.empty()) {
Expand Down Expand Up @@ -1241,6 +1316,28 @@ void CryptoContextImpl<DCRTPoly>::EvalMultInPlace(double scalar, Ciphertext<DCRT
EvalMultInPlace(ct1, scalar);
}

void CryptoContextImpl<DCRTPoly>::EvalMultInPlace(Ciphertext<DCRTPoly>& ct1, std::complex<double> scalar) {

// Fall back to CPU.
if (this->devices.empty()) {

auto& context = std::any_cast<const lbcrypto::CryptoContext<lbcrypto::DCRTPoly>&>(this->cpu);
auto& ct1Impl = std::any_cast<lbcrypto::Ciphertext<lbcrypto::DCRTPoly>&>(ct1->cpu);
context->EvalMultInPlace(ct1Impl, scalar);
return;
}

// GPU path.
this->LoadCiphertext(ct1);

auto res_gpu = std::static_pointer_cast<FIDESlib::CKKS::Ciphertext>(this->GetDeviceCiphertext(ct1->gpu));
res_gpu->multScalar(scalar);
}

void CryptoContextImpl<DCRTPoly>::EvalMultInPlace(std::complex<double> scalar, Ciphertext<DCRTPoly>& ct1) {
EvalMultInPlace(ct1, scalar);
}

Ciphertext<DCRTPoly> CryptoContextImpl<DCRTPoly>::EvalMultMutable(Ciphertext<DCRTPoly>& ct1, Ciphertext<DCRTPoly>& ct2) {
return EvalMult(ct1, ct2);
}
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9 changes: 9 additions & 0 deletions api/CryptoContext.hpp
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Expand Up @@ -9,6 +9,7 @@
#include <shared_mutex>
#include <unordered_map>
#include <vector>
#include <complex>

#include "CCParams.hpp"
#include "Ciphertext.hpp"
Expand Down Expand Up @@ -115,11 +116,15 @@ template <> class CryptoContextImpl<DCRTPoly> {
Ciphertext<DCRTPoly> EvalAdd(Plaintext& pt, const Ciphertext<DCRTPoly>& ct);
Ciphertext<DCRTPoly> EvalAdd(const Ciphertext<DCRTPoly>& ct, double scalar);
Ciphertext<DCRTPoly> EvalAdd(double scalar, const Ciphertext<DCRTPoly>& ct);
Ciphertext<DCRTPoly> EvalAdd(const Ciphertext<DCRTPoly>& ct, std::complex<double> scalar);
Ciphertext<DCRTPoly> EvalAdd(std::complex<double> scalar, const Ciphertext<DCRTPoly>& ct);
void EvalAddInPlace(Ciphertext<DCRTPoly>& ct1, const Ciphertext<DCRTPoly>& ct2);
void EvalAddInPlace(Ciphertext<DCRTPoly>& ct1, Plaintext& pt);
void EvalAddInPlace(Plaintext& pt, Ciphertext<DCRTPoly>& ct1);
void EvalAddInPlace(Ciphertext<DCRTPoly>& ct1, double scalar);
void EvalAddInPlace(double scalar, Ciphertext<DCRTPoly>& ct1);
void EvalAddInPlace(Ciphertext<DCRTPoly>& ct1, std::complex<double> scalar);
void EvalAddInPlace(std::complex<double> scalar, Ciphertext<DCRTPoly>& ct1);
Ciphertext<DCRTPoly> EvalAddMutable(Ciphertext<DCRTPoly>& ct1, Ciphertext<DCRTPoly>& ct2);
Ciphertext<DCRTPoly> EvalAddMutable(Ciphertext<DCRTPoly>& ct, Plaintext& pt);
Ciphertext<DCRTPoly> EvalAddMutable(Plaintext& pt, Ciphertext<DCRTPoly>& ct);
Expand All @@ -146,9 +151,13 @@ template <> class CryptoContextImpl<DCRTPoly> {
Ciphertext<DCRTPoly> EvalMult(Plaintext& pt, const Ciphertext<DCRTPoly>& ct1);
Ciphertext<DCRTPoly> EvalMult(const Ciphertext<DCRTPoly>& ct1, double scalar);
Ciphertext<DCRTPoly> EvalMult(double scalar, const Ciphertext<DCRTPoly>& ct1);
Ciphertext<DCRTPoly> EvalMult(const Ciphertext<DCRTPoly>& ct1, std::complex<double> scalar);
Ciphertext<DCRTPoly> EvalMult(std::complex<double> scalar, const Ciphertext<DCRTPoly>& ct1);
void EvalMultInPlace(Ciphertext<DCRTPoly>& ct1, Plaintext& pt);
void EvalMultInPlace(Ciphertext<DCRTPoly>& ct1, double scalar);
void EvalMultInPlace(double scalar, Ciphertext<DCRTPoly>& ct1);
void EvalMultInPlace(Ciphertext<DCRTPoly>& ct1, std::complex<double> scalar);
void EvalMultInPlace(std::complex<double> scalar, Ciphertext<DCRTPoly>& ct1);
Ciphertext<DCRTPoly> EvalMultMutable(Ciphertext<DCRTPoly>& ct1, Ciphertext<DCRTPoly>& ct2);
Ciphertext<DCRTPoly> EvalMultMutable(Ciphertext<DCRTPoly>& ct1, Plaintext& pt);
Ciphertext<DCRTPoly> EvalMultMutable(Plaintext& pt, Ciphertext<DCRTPoly>& ct1);
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5 changes: 5 additions & 0 deletions api/Definitions.hpp
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Expand Up @@ -86,6 +86,11 @@ enum SecurityLevel {
HEStd_NotSet,
};

enum CKKSDataType {
REAL = 0,
COMPLEX,
};

} // namespace fideslib

#endif
1 change: 1 addition & 0 deletions other/GPUTest.cpp
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@@ -1,5 +1,6 @@
#include <cuda_runtime.h>
#include <iostream>
#include <tuple>

int main() {
int deviceCount, device;
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91 changes: 91 additions & 0 deletions src/CKKS/Ciphertext.cpp
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Expand Up @@ -732,6 +732,97 @@ void Ciphertext::addScalar(const double c) {
//}
}

void Ciphertext::addScalar(const std::complex<double> c) {
CudaNvtxRange r(std::string{std::source_location::current().function_name()}.substr(23 + strlen(loc)));
CKKS::SetCurrentContext(cc_);
op_count[OPS::ADDSCALAR]++;

auto elem1 = cc.ElemForEvalAddOrSub(c0.getLevel(), std::fabs(c.real()), this->NoiseLevel);
auto elem2 = cc.ElemForEvalAddOrSub(c0.getLevel(), std::fabs(c.imag()), this->NoiseLevel);

uint32_t sizeQl = c0.getLevel() + 1;

std::vector<uint64_t> moduli(sizeQl);
for (int i = 0; i < sizeQl; ++i)
moduli[i] = cc.prime[i].p;

std::vector<std::vector<uint64_t>> data;
for (uint32_t i = 0; i < sizeQl; i++) {
std::vector<uint64_t> vec(cc.N, 0);
// Code works for positive values only, doesn't work for negative values.
vec[0] = (c.real() > 0) ? elem1[i] % (moduli[i]) : (-elem1[i] % (moduli[i]) + moduli[i]) % (moduli[i]);
vec[cc.N / 2] = (c.imag() > 0) ? elem2[i] % (moduli[i]) : (-elem2[i] % (moduli[i]) + moduli[i]) % (moduli[i]);
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@lawrencekhlim lawrencekhlim Feb 8, 2026

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There's a bug here on lines 753 and 754 for addition of negative complex numbers, whether the real or imaginary part is negative. Apologies, I didn't realize I tested it further just now. The multiplication doesn't have the same problems.

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@carlostriste carlostriste Feb 11, 2026

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Any idea of what causes this?

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@lawrencekhlim lawrencekhlim Feb 11, 2026

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I think the cause is that those two lines don't quite match up to what OpenFHE has in these two lines. Specifically, the mod.ModSub(elemsRe[i], mod) in OpenFHE (which is used when the real and likewise imaginary part are negative) doesn't match with (-elem1[i] % (moduli[i]) + moduli[i]) % (moduli[i]). It's possible that the positive part may have a subtle bug as well.

// End code that only works for positive values.
data.push_back(vec);
}

RNSPoly elemComplex(cc, data);
elemComplex.NTT(cc.batch, true);
c0.add(elemComplex);
}

void Ciphertext::multScalar(const std::complex<double> c, bool rescale) {
CudaNvtxRange r(std::string{std::source_location::current().function_name()}.substr(23 + strlen(loc)));
CKKS::SetCurrentContext(cc_);
op_count[OPS::MULTSCALAR]++;

if (cc.rescaleTechnique == FLEXIBLEAUTO || cc.rescaleTechnique == FLEXIBLEAUTOEXT ||
cc.rescaleTechnique == FIXEDAUTO) {
if (NoiseLevel == 2)
this->rescale();
}
assert(this->NoiseLevel == 1);

auto elem1 = cc.ElemForEvalMult(c0.getLevel(), c.real());
auto elem2 = cc.ElemForEvalMult(c0.getLevel(), c.imag());

auto level0 = c0.getLevel();
auto level1 = c1.getLevel();
RNSPoly real0(cc, level0), imag0(cc, level0), real1(cc, level1), imag1(cc, level1);
real0.copy(c0);
imag0.copy(c0);
real1.copy(c1);
imag1.copy(c1);

real0.multScalar(elem1);
imag0.multScalar(elem2);
real1.multScalar(elem1);
imag1.multScalar(elem2);

uint32_t N = cc.N;
uint32_t M = 2 * N;

std::vector<std::vector<uint64_t>> poly;
uint32_t power = M / 4;
uint32_t powerReduced = power % M;
uint32_t index = power % N;
for (int i = 0; i <= c0.getLevel(); ++i) {
std::vector<uint64_t> vec(N, 0);
vec[index] = powerReduced < N ? 1 : cc.prime[0].p - 1;
poly.push_back(vec);
}
RNSPoly monomial(cc, poly);
monomial.NTT(cc.batch, true);

imag0.multElement(monomial);
imag1.multElement(monomial);
c0.add(real0, imag0);
c1.add(real1, imag1);

// Manage metadata
NoiseLevel += 1;
NoiseFactor *= cc.param.ScalingFactorReal.at(c0.getLevel());
if (rescale) {
NoiseFactor /= cc.param.ModReduceFactor.at(c0.getLevel());
NoiseLevel -= 1;
}

if (rescale) {
c0.rescale();
c1.rescale();
}
}

void Ciphertext::automorph(const int index, const int br) {
CudaNvtxRange r(std::string{ sc::current().function_name() }.substr());
CKKS::SetCurrentContext(cc_);
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27 changes: 27 additions & 0 deletions src/CKKS/Ciphertext.cuh
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Expand Up @@ -6,6 +6,7 @@
#define FIDESLIB_CKKS_CIPHERTEXT_CUH

#include <source_location>
#include <complex>
#include "RNSPoly.cuh"
#include "forwardDefs.cuh"
#include "openfhe-interface/RawCiphertext.cuh"
Expand Down Expand Up @@ -210,6 +211,18 @@ class Ciphertext {
*/
void addScalar(const double c);

/**
* @brief Adds a scalar (complex) to both polynomial components.
*
* The scalar is first converted to the appropriate modulus representation
* via `ElemForEvalAddOrSub`. The sign of the scalar is handled by
* converting the element to its complement when `c < 0`. No metadata
* updates are performed.
*
* @param c Scalar value to add.
*/
void addScalar(const std::complex<double> c);

/**
* @brief Multiplies *this* ciphertext by a plaintext.
*
Expand Down Expand Up @@ -314,6 +327,20 @@ class Ciphertext {
*/
void multScalar(const Ciphertext& b, const double c, bool rescale = false);

/**
* @brief Multiplies both polynomial components by a complex scalar, performing necessary checks.
*
* For flexible rescaling techniques the method may rescale the ciphertext
* when the noise level is 2. The scalar is converted using
* `ElemForEvalMult` and the multiplication is applied to both components.
* Metadata (noise level/factor) is updated accordingly; if `rescale`
* is true and the technique is `FIXEDMANUAL`, a rescaling step follows.
*
* @param c Scalar multiplier.
* @param rescale Perform rescaling after multiplication if true.
*/
void multScalar(const std::complex<double> c, bool rescale = false);

/**
* @brief Squares the ciphertext (i.e., multiplies it by itself).
*
Expand Down
2 changes: 1 addition & 1 deletion src/CKKS/Context.cu
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Expand Up @@ -755,7 +755,7 @@ void ContextData::PrepareNCCLCommunication() {
NCCLCHECK(
ncclCommRegister(GPUrank[g], top_limb_buffer2[i], sizeof(uint64_t) * N, &top_limb_buffer2_handle[i]));
#else
cudaMalloc((void**)&top_limb_buffer[i], sizeof(uint63_t) * N);
cudaMalloc((void**)&top_limb_buffer[i], sizeof(uint64_t) * N);
cudaMalloc((void**)&top_limb_buffer2[i], sizeof(uint64_t) * N);
#endif
} else {
Expand Down