// Program done on 25/01/2024 by AMALJITH A
// To develop a C program for matrix calculation in arduino and show the resultant matrix in the serial monitor
//the input for Matrix A and Matrix B is given through serial monitor input and the Resultant Matrix is displayed in serial monitor.

// Assign a max_size for your matrix according to your requirement
const int MAX_SIZE = 10;

//Variable declaration to store the dimension of matrices A and B
int rowsA, colsA, rowsB, colsB;

void setup() {
  //to initialize serial communication
  Serial.begin(9600);
}

void loop() {
  // Input matrix dimensions
  Serial.println("Enter the dimensions of matrix A (rows x columns): ");
  readMatrixDimensions(rowsA, colsA);

  Serial.println("Enter the dimensions of matrix B (rows x columns): ");
  readMatrixDimensions(rowsB, colsB);

  // Check if dimensions are valid for multiplication
  if (colsA != rowsB) {
    Serial.println("Error: Column of matrix A must be equal to the rows of matrix B.");
    return;
  }

  // Input elements for matrix A
  int matrixA[MAX_SIZE][MAX_SIZE];
  Serial.println("Enter elements for matrix A:");
  if (!inputMatrix(matrixA, rowsA, colsA)) {
    return; // Error occurred
  }

  // Input elements for matrix B
  int matrixB[MAX_SIZE][MAX_SIZE];
  Serial.println("Enter elements for matrix B:");
  if (!inputMatrix(matrixB, rowsB, colsB)) {
    return; // Error occurred
  }

  // Display matrices
  displayMatrix(matrixA, rowsA, colsA);
  displayMatrix(matrixB, rowsB, colsB);

  // Multiply matrices
  int result[MAX_SIZE][MAX_SIZE];
  multiplyMatrices(matrixA, matrixB, result);

  // Display result
  displayMatrix(result, rowsA, colsB);
}

// Function to input matrix dimensions and to store the dimension of matrices given through serial monitor
void readMatrixDimensions(int &rows, int &cols) {
  while (!Serial.available());
  String input = Serial.readStringUntil('\n');
  sscanf(input.c_str(), "%d %d", &rows, &cols);
}

// Function to input elements for Matrices
bool inputMatrix(int matrix[MAX_SIZE][MAX_SIZE], int rows, int cols) {
  int elementsExpected = rows * cols;

  for (int i = 0; i < rows; i++) {
    for (int j = 0; j < cols; j++) {
      while (!Serial.available());
      if (Serial.peek() == '\n') {
        Serial.read(); //To consume newline
        return false;
      }
      matrix[i][j] = Serial.parseInt();
      if (Serial.available() && Serial.peek() == '\n') {
        Serial.read(); //To consume newline
      }
    }
  }
  // to print the error if the user entered more elements than the size of a matrix
  if (Serial.available()) {
    Serial.println("Error: Extra characters after the matrix input.");
    return false;
  }

  return true;
}

// Function to print and display the matrices
void displayMatrix(int matrix[MAX_SIZE][MAX_SIZE], int rows, int cols) {
  Serial.println("Matrix:");
  for (int i = 0; i < rows; i++) {
    for (int j = 0; j < cols; j++) {
      Serial.print(matrix[i][j]);
      Serial.print("\t");
    }
    Serial.println();
  }
  Serial.println();
}

// Function for matrix multiplication
void multiplyMatrices(int A[MAX_SIZE][MAX_SIZE], int B[MAX_SIZE][MAX_SIZE], int result[MAX_SIZE][MAX_SIZE]) {
  for (int i = 0; i < rowsA; i++) {
    for (int j = 0; j < colsB; j++) {
      result[i][j] = 0;
      for (int k = 0; k < colsA; k++) {
        result[i][j] += A[i][k] * B[k][j];
      }
    }
  }
}