FIX: Fixed generating of isotropic data

src/DataSet/DataSet.cpp

@@ -33,13 +33,24 @@ DataSet::DataSet(std::vector<std::pair<std::vector<double>, std::vector<double>>
 DataSet::DataSet(double lower_bound, double upper_bound, unsigned int size, double output) {
     std::vector<std::pair<std::vector<double>, std::vector<double>>> new_data_vec;
     this->data = new_data_vec;
-    this->n_elements = size;
+    this->n_elements = 0;
     this->input_dim = 1;
     this->output_dim = 1;
 
     this->add_isotropic_data(lower_bound, upper_bound, size, output);
 }
 
+DataSet::DataSet(std::vector<double> bounds, unsigned int no_elems_in_one_dim, std::vector<double> (*output_func)(std::vector<double>), unsigned int output_dim) {
+    std::vector<std::pair<std::vector<double>, std::vector<double>>> new_data_vec;
+    this->data = new_data_vec;
+    this->input_dim = bounds.size()/2;
+    this->output_dim = output_dim;
+    this->n_elements = 0;
+
+    this->add_isotropic_data(bounds, no_elems_in_one_dim, output_func);
+}
+
+
 void DataSet::add_data_pair(std::vector<double> inputs, std::vector<double> outputs) {
     if(inputs.size() != this->input_dim) {
         throw InvalidDimension("Bad input dimension.");
@@ -66,6 +77,33 @@ void DataSet::add_isotropic_data(double lower_bound, double upper_bound, unsigne
         inp = {frac*i};
         this->data.emplace_back(std::make_pair(inp, out));
     }
+
+    this->n_elements += size;
+}
+
+void DataSet::add_isotropic_data(std::vector<double> bounds, unsigned int no_elems_in_one_dim, std::vector<double> (*output_func)(std::vector<double>)) {
+    // TODO add check of dataset dimensions
+
+    std::vector<std::vector<double>> grid;
+    std::vector<double> tmp;
+    double frac;
+
+    for(unsigned int i = 0; i < bounds.size(); i += 2) {
+        frac = (bounds[i] + bounds[i+1]) / (no_elems_in_one_dim - 1);
+        tmp.clear();
+        for(double j = bounds[i]; j <= bounds[i+1]; j += frac) {
+            tmp.emplace_back(j);
+        }
+
+        grid.emplace_back(tmp);
+    }
+
+    grid = this->cartesian_product(&grid);
+
+    for(const auto& vec : grid) {
+        this->n_elements++;
+        this->data.emplace_back(std::make_pair(vec, output_func(vec)));
+    }
 }
 
 std::vector<std::pair<std::vector<double>, std::vector<double>>>* DataSet::get_data() {
@@ -110,4 +148,34 @@ void DataSet::store_text(std::string file_path) {
     boost::archive::text_oarchive oa(ofs);
     oa << *this;
     ofs.close();
+}
+
+template <class T>
+std::vector<std::vector<T>> DataSet::cartesian_product(const std::vector<std::vector<T>>* v) {
+    std::vector<std::vector<double>> v_combined_old, v_combined, v_tmp;
+    std::vector<double> tmp;
+
+    for(const auto& e : v->at(0)) {
+        tmp = {e};
+        v_combined.emplace_back(tmp);
+    }
+
+    for(unsigned int i = 1; i < v->size(); i++) {  // Iterate through remaining vectors of 'v'
+        v_combined_old = v_combined;
+        v_combined.clear();
+
+        for(const auto& e : v->at(i)) {
+            for(const auto& vec : v_combined_old) {
+                tmp = vec;
+                tmp.emplace_back(e);
+
+                /* Add only unique elements */
+                if(std::find(v_combined.begin(), v_combined.end(), tmp) == v_combined.end()) {
+                    v_combined.emplace_back(tmp);
+                }
+            }
+        }
+    }
+
+    return v_combined;
 }
\ No newline at end of file

src/DataSet/DataSet.h

@@ -12,6 +12,7 @@
 #include <boost/range/size_type.hpp>
 #include <exception>
 #include <string>
+#include <functional>
 
 /**
  * Class representing an error caused by an incorrect
@@ -61,6 +62,9 @@ private:
      */
     std::vector<std::pair<std::vector<double>, std::vector<double>>> data;
 
+    template <class T>
+    std::vector<std::vector<T>> cartesian_product(const std::vector<std::vector<T>>* v);
+
 protected:
     /**
      * Serialization function
@@ -165,6 +169,8 @@ public:
      */
     DataSet(double lower_bound, double upper_bound, unsigned int size, double output);
 
+    DataSet(std::vector<double> bounds, unsigned int no_elems_in_one_dim, std::vector<double> (*output_func)(std::vector<double>), unsigned int output_dim);
+
     /**
      * Getter for number of elements
      * @return Number of elements in the data set
@@ -212,6 +218,20 @@ public:
      */
     void add_isotropic_data(double lower_bound, double upper_bound, unsigned int size, double output);
 
+    /**
+     * Adds a new data with input values equidistantly positioned
+     * over the certain interval and the output value
+     * being constant
+     *
+     * Input can have arbitrary many dimensions,
+     * output can be an arbitrary function
+     *
+     * @param bounds Odd values are lower bounds and even values are corresponding upper bounds
+     * @param size Number of input-output pairs generated
+     * @param output_func Function determining output value
+     */
+    void add_isotropic_data(std::vector<double> bounds, unsigned int no_elems_in_one_dim, std::vector<double> (*output_func)(std::vector<double>));
+
     //TODO Chebyshev - ch. interpolation points, i-th point = cos(i*alpha) from 0 to pi
 
     /**