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Depth-preserving option for cut rewriting #352

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Merged
merged 2 commits into from
May 24, 2020
Merged

Depth-preserving option for cut rewriting #352

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d93c84c
Depth-preserving option for cut rewriting.
msoeken May 24, 2020
ede6b3a
Problems on Windows build.
msoeken May 24, 2020
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2 changes: 1 addition & 1 deletion CMakeLists.txt
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Original file line number Diff line number Diff line change
Expand Up @@ -26,7 +26,7 @@ if(UNIX)
endif()
endif()
if(MSVC)
add_compile_options(/EHsc)
add_compile_options(/EHsc /bigobj)
endif()

add_subdirectory(include)
Expand Down
52 changes: 42 additions & 10 deletions include/mockturtle/algorithms/cut_rewriting.hpp
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Expand Up @@ -48,6 +48,7 @@
#include "../utils/progress_bar.hpp"
#include "../utils/stopwatch.hpp"
#include "../views/cut_view.hpp"
#include "../views/depth_view.hpp"
#include "../views/fanout_view.hpp"
#include "cleanup.hpp"
#include "cut_enumeration.hpp"
Expand Down Expand Up @@ -96,6 +97,9 @@ struct cut_rewriting_params
/*! \brief Minimum candidate cut size override (in conflict graph) */
std::optional<uint32_t> min_cand_cut_size_override{};

/*! \brief If true, candidates are only accepted if they do not increase logic level of node. */
bool preserve_depth{false};

/*! \brief Show progress. */
bool progress{false};

Expand Down Expand Up @@ -671,7 +675,7 @@ void cut_rewriting_with_compatibility_graph( Ntk& ntk, RewritingFn&& rewriting_f
namespace detail
{

template<class Ntk, class RewritingFn, class NodeCostFn>
template<class NtkDest, class Ntk, class RewritingFn, class NodeCostFn>
struct cut_rewriting_impl
{
cut_rewriting_impl( Ntk const& ntk, RewritingFn const& rewriting_fn, cut_rewriting_params const& ps, cut_rewriting_stats& st )
Expand All @@ -680,14 +684,21 @@ struct cut_rewriting_impl
ps_( ps ),
st_( st ) {}

Ntk run()
NtkDest run()
{
stopwatch t( st_.time_total );

/* initial node map */
auto p = initialize_copy_network<Ntk>( ntk_ );
auto res = p.first;
auto old2new = p.second;
node_map<signal<Ntk>, Ntk> old2new( ntk_ );
Ntk res;
old2new[ntk_.get_constant( false )] = res.get_constant( false );
if ( ntk_.get_node( ntk_.get_constant( true ) ) != ntk_.get_node( ntk_.get_constant( false ) ) )
{
old2new[ntk_.get_constant( true )] = res.get_constant( true );
}
ntk_.foreach_pi( [&]( auto const& n ) {
old2new[n] = res.create_pi();
} );

/* enumerate cuts */
const auto cuts = call_with_stopwatch( st_.time_cuts, [&]() { return cut_enumeration<Ntk, true, cut_enumeration_cut_rewriting_cut>( ntk_, ps_.cut_enumeration_ps ); } );
Expand Down Expand Up @@ -741,8 +752,19 @@ struct cut_rewriting_impl

if ( ( gain > 0 || ( ps_.allow_zero_gain && gain == 0 ) ) && gain > best_gain )
{
best_gain = gain;
best_signal = f_new;
if constexpr ( has_level_v<Ntk> )
{
if ( !ps_.preserve_depth || res.level( res.get_node( f_new ) ) <= ntk_.level( n ) )
{
best_gain = gain;
best_signal = f_new;
}
}
else
{
best_gain = gain;
best_signal = f_new;
}
}

return true;
Expand Down Expand Up @@ -774,10 +796,10 @@ struct cut_rewriting_impl
res.create_po( ntk_.is_complemented( f ) ? res.create_not( old2new[f] ) : old2new[f] );
} );

res = cleanup_dangling( res );
NtkDest ret = cleanup_dangling<NtkDest>( res );

/* new costs */
return costs<Ntk, NodeCostFn>( res ) > orig_cost ? ntk_ : res;
return costs<NtkDest, NodeCostFn>( ret ) > orig_cost ? static_cast<NtkDest>( ntk_ ) : ret;
}

private:
Expand Down Expand Up @@ -817,7 +839,17 @@ template<class Ntk, class RewritingFn, class NodeCostFn = unit_cost<Ntk>>
Ntk cut_rewriting( Ntk const& ntk, RewritingFn const& rewriting_fn = {}, cut_rewriting_params const& ps = {}, cut_rewriting_stats* pst = nullptr )
{
cut_rewriting_stats st;
const auto result = detail::cut_rewriting_impl<Ntk, RewritingFn, NodeCostFn>( ntk, rewriting_fn, ps, st ).run();
const auto result = [&]() {
if ( ps.preserve_depth )
{
depth_view<Ntk, NodeCostFn> depth_ntk{ntk};
return detail::cut_rewriting_impl<Ntk, depth_view<Ntk, NodeCostFn>, RewritingFn, NodeCostFn>( depth_ntk, rewriting_fn, ps, st ).run();
}
else
{
return detail::cut_rewriting_impl<Ntk, Ntk, RewritingFn, NodeCostFn>( ntk, rewriting_fn, ps, st ).run();
}
}();

if ( ps.verbose )
{
Expand Down