/*

    This program is part of the TACLeBench benchmark suite.
    Version V 1.x

    Name: minver

    Author: Sung-Soo Lim

    Function: Matrix inversion for 3x3 floating point matrix.

    Source: SNU-RT Benchmark Suite, via MRTC
           http://www.mrtc.mdh.se/projects/wcet/wcet_bench/minver/minver.c

    Changes: a brief summary of major functional changes (not formatting)

    License: may be used, modified, and re-distributed freely, but
             the SNU-RT Benchmark Suite must be acknowledged

*/

/*
    This program is derived from the SNU-RT Benchmark Suite for Worst
    Case Timing Analysis by Sung-Soo Lim

    Original source: Turbo C Programming for Engineering by Hyun Soo Ahn
*/

/*
    Forward declaration of functions
*/

int minver_minver( int side, double eps );
int minver_mmul( int row_a, int col_a, int row_b, int col_b );
double minver_fabs( double n );
void minver_init();
int minver_return();
void minver_main();
int main( void );

/*
    Declaration of global variables
*/

double  minver_a[ 3 ][ 3 ] = {
  {3.0, -6.0,  7.0},
  {9.0,  0.0, -5.0},
  {5.0, -8.0,  6.0},
};
double minver_b[ 3 ][ 3 ];
double minver_c[ 3 ][ 3 ];
double minver_aa[ 3 ][ 3 ];
double minver_a_i[ 3 ][ 3 ];
double minver_det;

/*
    Arithmetic math functions
*/


double minver_fabs( double n )
{
  double f;

  if ( n >= 0 )
    f = n;
  else
    f = -n;
  return f;
}


int  minver_mmul( int row_a, int col_a, int row_b, int col_b )
{
  int i, j, k, row_c, col_c;
  double w;

  row_c = row_a;
  col_c = col_b;

  if ( row_c < 1 || row_b < 1 || col_c < 1 || col_a != row_b )
    return ( 999 );

  _Pragma( "loopbound min 3 max 3" )
  for ( i = 0; i < row_c; i++ ) {
    _Pragma( "loopbound min 3 max 3" )
    for ( j = 0; j < col_c; j++ ) {
      w = 0.0;
      _Pragma( "loopbound min 3 max 3" )
      for ( k = 0; k < row_b; k++ )
        w += minver_a[ i ][ k ] * minver_b[ k ][ j ];

      minver_c[ i ][ j ] = w;

    }
  }
  return ( 0 );

}


int minver_minver( int side, double eps )
{

  int work[ 500 ], i, j, k, iw;
  int r = 0;
  double w = 0, wmax, pivot, api, w1;

  if ( side < 2 || side > 500 || eps <= 0.0 )
    return ( 999 );
  w1 = 1.0;
  _Pragma( "loopbound min 3 max 3" )
  for ( i = 0; i < side; i++ )
    work[ i ] = i;
  _Pragma( "loopbound min 3 max 3" )
  for ( k = 0; k < side; k++ ) {
    wmax = 0.0;
    _Pragma( "loopbound min 1 max 3" )
    for ( i = k; i < side; i++ ) {
      w = minver_fabs( minver_a[ i ][ k ] );
      if ( w > wmax ) {
        wmax = w;
        r = i;
      }
    }
    pivot = minver_a[ r ][ k ];
    api = minver_fabs( pivot );
    if ( api <= eps ) {
      minver_det = w1;
      return ( 1 );
    }
    w1 *= pivot;
    if ( r != k ) {
      w1 = -w;
      iw = work[ k ];
      work[ k ] = work[ r ];
      work[ r ] = iw;
      _Pragma( "loopbound min 3 max 3" )
      for ( j = 0; j < side; j++ ) {
        w = minver_a[ k ][ j ];
        minver_a[ k ][ j ] = minver_a[ r ][ j ];
        minver_a[ r ][ j ] = w;
      }
    }
    _Pragma( "loopbound min 3 max 3" )
    for ( i = 0; i < side; i++ )
      minver_a[ k ][ i ] /= pivot;
    _Pragma( "loopbound min 3 max 3" )
    for ( i = 0; i < side; i++ ) {
      if ( i != k ) {
        w = minver_a[ i ][ k ];
        if ( w != 0.0 ) {
          _Pragma( "loopbound min 3 max 3" )
          for ( j = 0; j < side; j++ ) {
            if ( j != k ) minver_a[ i ][ j ] -= w * minver_a[ k ][ j ];
          }
          minver_a[ i ][ k ] = -w / pivot;

        }
      }
    }
    minver_a[ k ][ k ] = 1.0 / pivot;
  }
  _Pragma( "loopbound min 3 max 3" )
  for ( i = 0; i < side; ) {
    _Pragma( "loopbound min 1 max 3" )
    while ( 1 ) {
      k = work[ i ];
      if ( k == i ) break;
      iw = work[ k ];
      work[ k ] = work[ i ];
      work[ i ] = iw;
      _Pragma( "loopbound min 3 max 3" )
      for ( j = 0; j < side; j++ ) {
        w = minver_a [k ][ i ];
        minver_a[ k ][ i ] = minver_a[ k ][ k ];
        minver_a[ k ][ k ] = w;
      }
    }
    i++;
  }
  minver_det = w1;
  return ( 0 );

}

/*
    Initialization- and return-value-related functions
*/

void minver_init()
{
  int i, j;
  volatile int x = 0;

  _Pragma( "loopbound min 3 max 3" )
  for ( i = 0; i < 3; i++ ) {
    _Pragma( "loopbound min 3 max 3" )
    for ( j = 0; j < 3; j++ )
      minver_a[ i ][ j ] += x;
  }
}


int minver_return()
{
  int i, j;
  double check_sum = 0;

  _Pragma( "loopbound min 3 max 3" )
  for ( i = 0; i < 3; i++ ) {
    _Pragma( "loopbound min 3 max 3" )
    for ( j = 0; j < 3; j++ )
      check_sum += minver_a_i[ i ][ j ];
  }
  /* Avoid double comparison */
  return ( int )( check_sum * 100 ) != 48;
}


/*
    Main functions
*/


void _Pragma( "entrypoint" ) minver_main()
{
  int i, j;
  double eps;
  eps = 1.0e-6;
  _Pragma( "loopbound min 3 max 3" )
  for ( i = 0; i < 3; i++ ) {
    _Pragma( "loopbound min 3 max 3" )
    for ( j = 0; j < 3; j++ )
      minver_aa[ i ][ j ] = minver_a[ i ][ j ];
  }

  minver_minver( 3, eps );
  _Pragma( "loopbound min 3 max 3" )
  for ( i = 0; i < 3; i++ ) {
    _Pragma( "loopbound min 3 max 3" )
    for ( j = 0; j < 3; j++ )
      minver_a_i[ i ][ j ] = minver_a[ i ][ j ];
  }

  minver_mmul( 3, 3, 3, 3 );
}


int main( void )
{
  minver_init();
  minver_main();

  return ( minver_return() );
}