Basic-matrix-operations-no-iostream.ino

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#include <Linear_Algebra.h> // Include the library first
 
#include <Linear_Algebra.h> // Include the library first
 
// Then include the necessary headers:
#include <include/linalg/HouseholderQR.hpp> 
#include <include/linalg/Matrix.hpp>
 
void setup() {
  Serial.begin(115200);
  while (!Serial)
    ;
 
  Serial.println("Solve system Ax = v");
  Serial.println("-------------------\n");
  SquareMatrix A = {
    {1, 6, 2},
    {3, 2, 1},
    {5, 1, 3},
  };
  Vector x = Vector::ones(3);
  Vector v = A * x;
 
  HouseholderQR qr(A); // QR factorization
  Vector x_solution = qr.solve(v);
 
  Serial.println("A = ");
  Serial.println(A);
  Serial.println("v =");
  Serial.println(v);
  Serial.println("QR factorization of A:");
  Serial.println("Q =");
  Serial.println(qr.get_Q());
  Serial.println("R =");
  Serial.println(qr.get_R());
  Serial.println("solution x =");
  Serial.println(x_solution);
 
  Serial.println("Basic matrix operations");
  Serial.println("-----------------------\n");
  Matrix B = {
    {1, 2},
    {3, 4},
    {5, 6},
  };
  Matrix C = {
    {1, 2, 3},
    {4, 5, 6},
  };
  Matrix D = {
    {10, 11},
    {12, 13},
  };
  Matrix E = C * B + D;
  Serial.println("C×B + D =");
  Serial.println(E);
 
  Serial.println("Basic vector operations");
  Serial.println("-----------------------\n");
  RowVector a = {1, 2, 3};
  RowVector b = {4, 6, 5};
  RowVector c = a.cross(b);
  double d = a.dot(b);
  Serial.print("a   =      ");
  Serial.print(a);
  Serial.print("b   =      ");
  Serial.print(b);
  Serial.print("a×b =      ");
  Serial.print(c);
  Serial.print("a·b =      ");
  Serial.println(d);
  Serial.println();
 
  Serial.println("Element access");
  Serial.println("--------------\n");
  Serial.print("A[2,0] = ");
  Serial.println(A(2, 0));
  //               │  └─ column
  //               └──── row
  Serial.println("A[2,0] ← 100");
  A(2, 0) = 100; // assign a new value to the element
  Serial.println("A =");
  Serial.println(A);
}
 
void loop() {}