Routine Name: matrixScale

Author: Christopher Johnson

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

Declared in “matrix.h”

Description/Purpose: Multiplies matrix by scalar

Input: Matrix a and double s, where Matrix is a typedef of std::vector<std::vector<double>>.

Output: Returns a Matrix, of size equal to the input matrix.

Usage/Example:

A Matrix must first be defined, and then the method may be called.

Matrix b(5, Vector(5,1)); \\5*5 matrix of all ones
double s = 5.1;
std::cout << "B * s is\n";
printMatrix(matrixScale(b,s));

Output from the lines above:

B * s is
[[5.1,5.1,5.1,5.1,5.1],
 [5.1,5.1,5.1,5.1,5.1],
 [5.1,5.1,5.1,5.1,5.1],
 [5.1,5.1,5.1,5.1,5.1],
 [5.1,5.1,5.1,5.1,5.1]]

Implementation/Code: The following is the code for matrixScale(a,s)

Matrix matrixScale(Matrix a, double s)
{
    Matrix sol = a;

    for (int i=0;i<a.size();++i)
        for (int j=0;j<a[0].size();j++)
            sol[i][j]*= s;

    return sol;
}

Last Modified: October/2017