vector_naive.cpp

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#include <cmath>
#include <cstdint>
#include <iostream>
#include <numeric>
#include <openGPMP/linalg/vector.hpp>
#include <stdexcept>
#include <vector>
 
/************************************************************************
 *
 * Standard/Naive Vector  Operations on vector<>
 *
 ************************************************************************/
 
// function to compute the cross product of two 3D vectors
void gpmp::linalg::std_cross_product(const std::vector<double> &vec1,
                                     const std::vector<double> &vec2,
                                     std::vector<double> &result) {
    result[0] = vec1[1] * vec2[2] - vec1[2] * vec2[1];
    result[1] = vec1[2] * vec2[0] - vec1[0] * vec2[2];
    result[2] = vec1[0] * vec2[1] - vec1[1] * vec2[0];
}
 
double gpmp::linalg::std_vector_norm(const std::vector<double> &vec) {
    double norm = 0.0;
    for (double value : vec) {
        norm += value * value;
    }
    return std::sqrt(norm);
}
 
// function to normalize a vector to have unit length
void gpmp::linalg::std_vector_normalize(const std::vector<double> &vec,
                                        std::vector<double> &result) {
    double norm = gpmp::linalg::std_vector_norm(vec);
    result.resize(vec.size());
    for (size_t i = 0; i < vec.size(); ++i) {
        result[i] = vec[i] / norm;
    }
}
 
// function to compute the projection of one vector onto another
void gpmp::linalg::std_vector_projection(const std::vector<double> &vec,
                                         const std::vector<double> &onto_vec,
                                         std::vector<double> &result) {
    double dot = std_dot_product(vec, onto_vec);
    double onto_vec_norm_sq = std_dot_product(onto_vec, onto_vec);
 
    result.resize(onto_vec.size());
    for (size_t i = 0; i < onto_vec.size(); ++i) {
        result[i] = (dot / onto_vec_norm_sq) * onto_vec[i];
    }
}
 
// function to compute the cross product of two 3D vectors of integers
void gpmp::linalg::std_cross_product(const std::vector<int> &vec1,
                                     const std::vector<int> &vec2,
                                     std::vector<int> &result) {
    result.resize(3);
    result[0] = vec1[1] * vec2[2] - vec1[2] * vec2[1];
    result[1] = vec1[2] * vec2[0] - vec1[0] * vec2[2];
    result[2] = vec1[0] * vec2[1] - vec1[1] * vec2[0];
}
 
double gpmp::linalg::std_vector_norm(const std::vector<int> &vec) {
    double norm = 0.0;
    for (int value : vec) {
        norm += value * value;
    }
    return std::sqrt(norm);
}
 
// function to normalize a vector of integers to have unit length
void gpmp::linalg::std_vector_normalize(const std::vector<int> &vec,
                                        std::vector<double> &result) {
    double norm = std_vector_norm(vec);
    result.resize(vec.size());
    for (size_t i = 0; i < vec.size(); ++i) {
        result[i] = static_cast<double>(vec[i]) / norm;
    }
}
 
// function to compute the projection of one vector of integers onto another
void gpmp::linalg::std_vector_projection(const std::vector<int> &vec,
                                         const std::vector<int> &onto_vec,
                                         std::vector<double> &result) {
    double dot = std_dot_product(vec, onto_vec);
    double onto_vec_norm_sq = std_dot_product(onto_vec, onto_vec);
 
    result.resize(onto_vec.size());
    for (size_t i = 0; i < onto_vec.size(); ++i) {
        result[i] = (dot / onto_vec_norm_sq) * onto_vec[i];
    }
}