Numeric.ino

Numeric

Example of using the standard library numeric functions.

Boards:

AVR, AVR USB, Nano Every, Nano 33, Due, Teensy 3.x, ESP8266, ESP32

This sketch creates an incremental array using the iota function, then computes the inner product of the vector with itself, and uses that to calculate the norm of the vector.

Output

v      = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
〈v, v〉 = 385
‖v‖    = 19.6214160

Written by PieterP, 2019-11-18
https://github.com/tttapa/Arduino-Helpers

 
#include <Arduino_Helpers.h>
 
#include <AH/Containers/Array.hpp>        // Array
#include <AH/Containers/ArrayHelpers.hpp> // For printing the array
#include <AH/STL/cmath>                   // std::sqrt
#include <AH/STL/numeric>                 // std::iota, std::inner_product
 
void setup() {
  Serial.begin(115200);
  while (!Serial)
    ;
 
  // Create an array with the elements [1, 2 ... 9, 10]
  Array<int, 10> vector;
  std::iota(std::begin(vector), std::end(vector), 1);
  Serial << "v      = [" << vector << ']' << endl;
 
  // Compute the inner product of vector with itself, with an initial sum of 0
  int sum_sq = std::inner_product(std::begin(vector), std::end(vector),
                                  std::begin(vector), 0);
  Serial << "〈v, v〉 = " << sum_sq << endl;
 
  // The 2-norm of a vector is the squareroot of the inner product with itself
  double norm = std::sqrt(sum_sq);
  Serial << "‖v‖    = " << setprecision(7) << norm << endl;
}
 
void loop() {}