Matrix-ADT

Matrix is a C++ library for basic linear algebra applications. It is inspired by the way that the Julia package LinearAlgebra handles matrices, although this library is not nearly as optimized as the Julia package.

Usage

#include "Matrix.h"

matrix mat_1();     // initializes an empty matrix
matrix mat_2(3);    // initializes an empty 3x3 matrix
matrix mat_3(3,2);  // initializes an empty 3x2 matrix

double a[9] = {1, 2, 3,
               4, 5, 6,
               7, 8, 9};
               
double b[6] = {1, 2,
               3, 4,
               5, 6};

matrix mat_4(3,a);    // initializes a 3x3 matrix with data
matrix mat_5(3,2,b);  // initializes a 3x2 matrix with data

matrix L(3), U(3);
mat_4.LU(L,U);      // Factors mat_4 into lower and upper triangular matrices

matrix Q(3), R(3);
mat_4.QR(Q,R);      // Factors mat_4 into an orthogonal matrix Q and upper triangular matrix R

double A_data[9] = {31, 25, 13, 64, 53, 46, 97, 68, 19};
double b_data[3] = {1, 2, 3};
matrix A(3,A_data), b(3,1,b_data), x;
x = linearSolve(A,b);   // Returns the solution x to the linear system A*x = b

double x1[5] = {1, 2, 4, 5, 7};
double y1[5] = {4, 8, 10, 12, 18};
matrix X1(5,1,x1), Y1(5,1,y1);
matrix C = fit(X1,Y1);  // Returns a 2x1 matrix with coefficients for a linear fit (C1*x + C2)

double x2[11] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
double y2[11] = {20, 15, 16, 18, 23, 30, 40, 55, 70, 86, 110};
matrix X2(11,1,x2), Y2(11,1,y2);
matrix C = fit(X2,Y2,2);  // Returns a 3x1 matrix with coefficients for a quadratic fit (C1*x^2 + C2*x + C3)