tableLookup.h

/* Copyright (C) 2012-2020 IBM Corp.
 * This program is Licensed under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance
 * with the License. You may obtain a copy of the License at
 *   http://www.apache.org/licenses/LICENSE-2.0
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License. See accompanying LICENSE file.
 */
#ifndef HELIB_TABLELOOKUP_H
#define HELIB_TABLELOOKUP_H
 
#include <functional>
#include <helib/EncryptedArray.h>
#include <helib/CtPtrs.h>
 
namespace helib {
 
// inline void convert(Ctxt& a, const Ctxt& b) { a=b; }
 
void computeAllProducts(CtPtrs& products,
                        const CtPtrs& array,
                        std::vector<zzX>* unpackSlotEncoding = nullptr);
 
void tableLookup(Ctxt& out,
                 const std::vector<zzX>& table,
                 const CtPtrs& idx,
                 std::vector<zzX>* unpackSlotEncoding = nullptr);
 
void tableWriteIn(const CtPtrs& table,
                  const CtPtrs& idx,
                  std::vector<zzX>* unpackSlotEncoding = nullptr);
 
void buildLookupTable(std::vector<zzX>& T, // encoded result is returned in T
                      std::function<double(double)> f,
                      long nbits_in, // number of precision bits
                      long scale_in, // scaling factor
                      long sign_in,  // 1: 2's complement signed, 0: unsigned
                      long nbits_out,
                      long scale_out,
                      long sign_out,
                      const EncryptedArray& ea);
 
} // namespace helib
 
#endif // ifndef HELIB_TABLELOOKUP_H