Routine Name: vectorNormL2

Author: Christopher Johnson

Language: C++11. Tested with g++ compiler.

Declared in “vectorCode.h”

Description/Purpose: Calculates the l2 norm of input vector.

Input: Vector v, typedef of std::vector<double>;

Output: A double, indicating the l2 norm of the input value.

Usage/Example: The user must first define a vector, after which the method may be called on the vector.

Vector a = {1,2,3};
std::cout << "Let the vector A be given as\n";
printVector(a);
std::cout << "The l2 norm of A is " << vectorNormL1(a) << std::endl;

Output from the lines above:

The l2 norm of A is 3.74166

Implementation/Code: The following is the code for vectorNormL2(v)

double vectorNormL2 (Vector v)
{
    double sum_of_squares = 0.0;
    for (int i=0; i<v.size(); i++)
        sum_of_squares+=v[i]*v[i];
    return sqrt(sum_of_squares);
}

Last Modified: October/2017