mindspore2022/mindspore/ccsrc/mindquantum/sparse.cc

125 lines
3.1 KiB
C++

/**
* Copyright 2021 Huawei Technologies Co., Ltd
*
* 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.
*/
#include "mindquantum/sparse.h"
namespace mindspore {
namespace mindquantum {
namespace sparse {
SparseMatrix BasiGateSparse(char g) {
SparseMatrix out(2, 2);
out.reserve(VectorXi::Constant(2, 2));
switch (g) {
case 'X':
case 'x':
out.insert(0, 1) = 1;
out.insert(1, 0) = 1;
break;
case 'Y':
case 'y':
out.insert(0, 1) = {0, -1};
out.insert(1, 0) = {0, 1};
break;
case 'Z':
case 'z':
out.insert(0, 0) = 1;
out.insert(1, 1) = -1;
break;
case '0':
out.insert(0, 0) = 1;
break;
case '1':
out.insert(1, 1) = 1;
break;
default:
out.insert(0, 0) = 1;
out.insert(1, 1) = 1;
break;
}
out.makeCompressed();
return out;
}
SparseMatrix IdentitySparse(int n_qubit) {
if (n_qubit == 0) {
int dim = 1UL << n_qubit;
SparseMatrix out(dim, dim);
out.reserve(VectorXi::Constant(dim, dim));
for (int i = 0; i < dim; i++) {
out.insert(i, i) = 1;
}
out.makeCompressed();
return out;
} else {
SparseMatrix out = BasiGateSparse('I');
for (int i = 1; i < n_qubit; i++) {
out = KroneckerProductSparse(out, BasiGateSparse('I')).eval();
}
return out;
}
}
SparseMatrix PauliTerm2Sparse(const PauliTerm &pt, Index _min, Index _max) {
int poi;
int n = pt.first.size();
SparseMatrix out;
if (pt.first[0].first == _min) {
out = BasiGateSparse(pt.first[0].second) * pt.second;
poi = 1;
} else {
out = BasiGateSparse('I') * pt.second;
poi = 0;
}
for (Index i = _min + 1; i <= _max; i++) {
if (poi == n) {
out = KroneckerProductSparse(IdentitySparse(_max - i + 1), out).eval();
break;
} else {
if (i == pt.first[poi].first) {
out = KroneckerProductSparse(BasiGateSparse(pt.first[poi++].second), out).eval();
} else {
out = KroneckerProductSparse(BasiGateSparse('I'), out).eval();
}
}
}
return out;
}
SparseMatrix GoodTerm2Sparse(const GoodTerm &gt, Index n_qubits) {
SparseMatrix out = PauliTerm2Sparse(gt.second[0], gt.first.second.first, gt.first.second.second);
for (Index i = 1; i < gt.second.size(); i++) {
out += PauliTerm2Sparse(gt.second[i], gt.first.second.first, gt.first.second.second);
}
out.prune({0.0, 0.0});
out *= gt.first.first;
out = KroneckerProductSparse(out, IdentitySparse(gt.first.second.first)).eval();
out = KroneckerProductSparse(IdentitySparse(n_qubits - gt.first.second.second - 1), out).eval();
return out;
}
} // namespace sparse
} // namespace mindquantum
} // namespace mindspore