// file: /data/courses/ece_1111/lectures/current/lecture_04/example.cc
//

// local include files
//
#include "example.h"

// function: main
//
// This is a simple program that prints to the terminal.
//
int main(int argc, const char** argv) {

  // decode the command line arguments
  //
  long nrows = atoi(argv[1]);
  long ncols = atoi(argv[2]);
  long niter = atoi(argv[3]);

  // echo the command line arguments
  //
  fprintf(stdout, "program name: %s\n", argv[0]);
  fprintf(stdout, "number of rows = %d\n", nrows);
  fprintf(stdout, "number of cols = %d\n", ncols);
  fprintf(stdout, "niter = %d\n", niter);

  // declare local variables
  //
  float* a = new float[nrows * ncols];
  float* b = new float[ncols * nrows];
  float* c = new float[nrows * nrows];

  // initialize a matrix
  //
  fprintf(stdout, "... initializing...\n");
  if (minit(a, nrows, ncols) == false) {
    fprintf(stdout, "%s: error initializing matrices\n", argv[0]);
  }
  if (minit(b, ncols, nrows) == false) {
    fprintf(stdout, "%s: error initializing matrices\n", argv[0]);
  }

  // print the matrices
  //
  fprintf(stdout, "... printing...\n");
  if (mprint(a, nrows, ncols) == false) {
    fprintf(stdout, "%s: error printing matrices\n", argv[0]);
  }
  if (mprint(b, ncols, nrows) == false) {
    fprintf(stdout, "%s: error printing matrices\n", argv[0]);
  }

  // multiply both matrices
  //
  for (long i = 0; i < niter; i++) {
    if (i % NITER == 0) {
      fprintf(stdout, "iteration no. %d\n", i);
    }
    
    if (mmult(c, a, b, nrows, ncols) == false) {
      fprintf(stdout, "%s: error multiplying matrices\n", argv[0]);
    }
  }

  // exit gracefully
  //
  return(0);
}

// function: mmult
//
// arguments:
//  float* c: output matrix
//  float* a: operands
//  float* b: operands
//  long nrows: number of rows
//  long ncols: number of cols
//
// return: returns a boolean value indicating status
//
// This method multiplies two matrices (c = a * b).
//
bool mmult(float* c, float* a, float* b, long nrows, long ncols) {

  // print an informational message
  //
  fprintf(stdout, "mmult: %d %d\n", nrows, ncols);

  // exit gracefully
  //
  return true;
}

// function: minit
//
// arguments:
//  float* a: operands
//  long nrows: number of rows
//  long ncols: number of cols
//
// return: returns a boolean value indicating status
//
// This method initializes a matrix.
//
bool minit(float* a, long nrows, long ncols) {

  // print an informational message
  //
  fprintf(stdout, "mmult: initializing (%d %d)\n", nrows, ncols);

  // loop over the rows
  //
  for (long i = 0; i < nrows; i++) {
    
    // loop over the cols
    //
    for (long j = 0; j < ncols; j++) {

      // set the value
      //
      if (i == j) {
	*a++ = (float)1.0;
      }
      else {
	*a++ = (float)0.0;
      }
    }
  }

  // exit gracefully
  //
  return true;
}

// function: mprint
//
// arguments:
//  float* a: operands
//  long nrows: number of rows
//  long ncols: number of cols
//
// return: returns a boolean value indicating status
//
// This method prints a matrix.
//
bool mprint(float* a, long nrows, long ncols) {

  // loop over the rows
  //
  for (long i = 0; i < nrows; i++) {

    // print the row
    //
    fprintf(stdout, "%5d:", i);

    // loop over the cols
    //
    for (long j = 0; j < ncols; j++) {

      // print the value
      //
      fprintf(stdout, "%10.4f ", *a++);
    }

    // print a new line
    //
    fprintf(stdout, "\n");
  }
  fprintf(stdout, "\n");

  // exit gracefully
  //
  return true;
}