CR.cpp

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/*
Created on Fri Jun 26 14:13:26 2020
Copyright 2020 Peter Rakyta, Ph.D.

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.

@author: Peter Rakyta, Ph.D.
*/
#include "CR.h"



//static tbb::spin_mutex my_mutex;
CR::CR() : R() {

    // A string labeling the gate operation
    name = "CR";

    // A string describing the type of the gate
    type = CR_OPERATION;

}



CR::CR(int qbit_num_in, int target_qbit_in, int control_qbit_in) : R(qbit_num_in, target_qbit_in) {

    // A string labeling the gate operation
    name = "CR";

    // A string describing the type of the gate
    type = CR_OPERATION;


    if (control_qbit_in >= qbit_num) {
       std::stringstream sstream;
       sstream << "The index of the control qubit is larger than the number of qubits in CR gate." << std::endl;
       print(sstream, 0);       
        throw sstream.str();
    }

    // The index of the qubit which acts as a control qubit (control_qbit >= 0) in controlled gates
    control_qbit = control_qbit_in;


}

CR::~CR() {

}




void 
CR::apply_to( Matrix_real& parameters, Matrix& input, int parallel ) {


    if (input.rows != matrix_size ) {
        std::string err("CR::apply_to: Wrong matrix size in CR gate apply.");
        throw err;    
    }


    double ThetaOver2, Phi, Lambda;

    ThetaOver2 = parameters[0];
    Phi = parameters[1]-M_PI/2;
    Lambda = -1.*parameters[1] + M_PI/2;
    
    Matrix u3_1qbit = calc_one_qubit_u3(ThetaOver2, Phi, Lambda );


    // apply the computing kernel on the matrix
    apply_kernel_to(u3_1qbit, input, false, parallel);

}



void 
CR::apply_from_right( Matrix_real& parameters, Matrix& input ) {


    if (input.cols != matrix_size ) {
     std::stringstream sstream;
     sstream << "Wrong matrix size in CR apply_from_right" << std::endl;
        print(sstream, 0);    
        throw "Wrong matrix size in CR apply_from_right";
    }

    double ThetaOver2, Phi, Lambda;

    ThetaOver2 = parameters[0];
    Phi = parameters[1]-M_PI/2;
    Lambda = -1.*parameters[1] + M_PI/2;
    

/*
    ThetaOver2 = theta0;
    Phi = parameters[0];
    Lambda = lambda0;
*/
/*
Phi = Phi + M_PI;
Phi = (1.0-std::cos(Phi/2))*M_PI;
Phi = Phi - M_PI;
*/
//Phi = 0.5*(1.0-std::cos(Phi))*M_PI;


    // get the U3 gate of one qubit
    Matrix u3_1qbit = calc_one_qubit_u3(ThetaOver2, Phi, Lambda );

    // apply the computing kernel on the matrix
    apply_kernel_from_right(u3_1qbit, input);

}


std::vector<Matrix> 
CR::apply_derivate_to( Matrix_real& parameters_mtx, Matrix& input, int parallel ) {

    if (input.rows != matrix_size ) {
     std::stringstream sstream;
     sstream << "Wrong matrix size in CR gate apply" << std::endl;
        print(sstream, 0);       
        throw "Wrong matrix size in CR gate apply";
    }

    std::vector<Matrix> ret;
    
    double ThetaOver2, Phi, Lambda;
    
    ThetaOver2 = parameters_mtx[0];
    Phi = parameters_mtx[1]-M_PI/2;
    Lambda = -1.*parameters_mtx[1] + M_PI/2;
    
    
    Matrix res_mtx = input.copy();
    Matrix u3_1qbit = calc_one_qubit_u3(ThetaOver2 + M_PI/2, Phi, Lambda );
    apply_kernel_to( u3_1qbit, res_mtx, true, parallel );
    ret.push_back(res_mtx);
    Matrix res_mtx2 = input.copy();
    u3_1qbit = calc_one_qubit_u3(ThetaOver2, Phi + M_PI/2, Lambda - M_PI/2 );
    u3_1qbit[0].real = 0.; 
    u3_1qbit[0].imag = 0.;
    u3_1qbit[3].real = 0.; 
    u3_1qbit[3].imag = 0.;
    apply_kernel_to( u3_1qbit, res_mtx2, true, parallel );
    ret.push_back(res_mtx2);
    
    return ret;


}


CR* CR::clone() {

    CR* ret = new CR(qbit_num, target_qbit, control_qbit);

    ret->set_parameter_start_idx( get_parameter_start_idx() );
    ret->set_parents( parents );
    ret->set_children( children );

    return ret;

}


Matrix_real 
CR::extract_parameters( Matrix_real& parameters ) {

    if ( get_parameter_start_idx() + get_parameter_num() > parameters.size()  ) {
        std::string err("CR::extract_parameters: Cant extract parameters, since the dinput arary has not enough elements.");
        throw err;     
    }

    Matrix_real extracted_parameters(1,2);

    extracted_parameters[0] = std::fmod( 2*parameters[ get_parameter_start_idx() ], 4*M_PI);
    extracted_parameters[1] = std::fmod( parameters[ get_parameter_start_idx() + 1 ], 2*M_PI);

    return extracted_parameters;

}