acd::ac_decomposition_impl Class Reference

#include <ac_decomposition.hpp>

Public Member Functions
	ac_decomposition_impl (uint32_t num_vars, ac_decomposition_params const &ps, ac_decomposition_stats *pst=nullptr)
int	run (word *ptt, unsigned delay_profile)
	Runs ACD using late arriving variables.
int	compute_decomposition ()
unsigned	get_profile ()
void	get_decomposition (unsigned char *decompArray)

Detailed Description

Definition at line 86 of file ac_decomposition.hpp.

Constructor & Destructor Documentation

ac_decomposition_impl()

acd::ac_decomposition_impl::ac_decomposition_impl ( uint32_t num_vars, ac_decomposition_params const & ps, ac_decomposition_stats * pst = nullptr )

inlineexplicit

Definition at line 102 of file ac_decomposition.hpp.

      : num_vars( num_vars ), ps( ps ), pst( pst )
  {
    std::iota( permutations.begin(), permutations.end(), 0 );
  }

Member Function Documentation

compute_decomposition()

int acd::ac_decomposition_impl::compute_decomposition ( )

inline

Definition at line 152 of file ac_decomposition.hpp.

  {
    if ( best_multiplicity == UINT32_MAX )
      return -1;
 
    /* compute isets */
    std::vector<STT> isets = compute_isets();
 
    generate_support_minimization_encodings();
 
    /* solves exactly only for small multiplicities */
    if ( best_multiplicity <= 4u )
      solve_min_support_exact( isets );
    else
      solve_min_support_heuristic( isets );
 
    /* unfeasible decomposition */
    assert( !best_bound_sets.empty() );
 
    return 0;
  }

get_decomposition()

void acd::ac_decomposition_impl::get_decomposition ( unsigned char * decompArray )

inline

Definition at line 189 of file ac_decomposition.hpp.

  {
    if ( best_free_set > num_vars )
      return;
 
    generate_decomposition();
    get_decomposition_abc( decompArray );
  }

get_profile()

unsigned acd::ac_decomposition_impl::get_profile ( )

inline

Definition at line 174 of file ac_decomposition.hpp.

  {
    unsigned profile = 0;
 
    if ( best_free_set > num_vars )
      return -1;
 
    for ( uint32_t i = 0; i < best_free_set; ++i )
    {
      profile |= 1 << permutations[i];
    }
 
    return profile;
  }

run()

int acd::ac_decomposition_impl::run ( word * ptt, unsigned delay_profile )

inline

Runs ACD using late arriving variables.

Definition at line 109 of file ac_decomposition.hpp.

  {
    /* truth table is too large for the settings */
    if ( num_vars > max_num_vars )
    {
      return -1;
    }
 
    uint32_t late_arriving = __builtin_popcount( delay_profile );
 
    /* relax maximum number of free set variables if a function has more variables */
    if ( num_vars > ps.max_free_set_vars + ps.lut_size )
    {
      ps.max_free_set_vars = num_vars - ps.lut_size;
    }
    if ( late_arriving > ps.max_free_set_vars )
    {
      return -1; /* on average avoiding this computation leads to better quality */
      // ps.max_free_set_vars = late_arriving;
    }
 
    /* return a high cost if too many late arriving variables */
    if ( late_arriving > ps.lut_size - 1 )
    {
      return -1;
    }
 
    /* convert to static TT */
    init_truth_table( ptt );
 
    /* permute late arriving variables to be the least significant */
    reposition_late_arriving_variables( delay_profile, late_arriving );
 
    /* run ACD trying different bound sets and free sets */
    if ( !find_decomposition( delay_profile, late_arriving ) )
    {
      return -1;
    }
 
    /* return number of levels */
    return delay_profile == 0 ? 2 : 1;
  }

---

The documentation for this class was generated from the following file:

• src/map/if/acd/ac_decomposition.hpp