/*
//@HEADER
// ************************************************************************
//
//                        Kokkos v. 2.0
//              Copyright (2014) Sandia Corporation
//
// Under the terms of Contract DE-AC04-94AL85000 with Sandia Corporation,
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// documentation and/or other materials provided with the distribution.
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// Questions? Contact Christian R. Trott (crtrott@sandia.gov)
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*/

#include <stdexcept>
#include <sstream>
#include <iostream>
#include <limits>

#include <Kokkos_Core.hpp>

namespace Test {

template< typename ScalarType, class DeviceType >
class ReduceFunctor
{
public:
  typedef DeviceType execution_space;
  typedef typename execution_space::size_type size_type;

  struct value_type {
    ScalarType value[3];
  };

  const size_type nwork;

  KOKKOS_INLINE_FUNCTION
  ReduceFunctor( const size_type & arg_nwork )
    : nwork( arg_nwork ) {}

  KOKKOS_INLINE_FUNCTION
  ReduceFunctor( const ReduceFunctor & rhs )
    : nwork( rhs.nwork ) {}

/*
  KOKKOS_INLINE_FUNCTION
  void init( value_type & dst ) const
  {
    dst.value[0] = 0;
    dst.value[1] = 0;
    dst.value[2] = 0;
  }
*/

  KOKKOS_INLINE_FUNCTION
  void join( volatile value_type & dst,
             const volatile value_type & src ) const
  {
    dst.value[0] += src.value[0];
    dst.value[1] += src.value[1];
    dst.value[2] += src.value[2];
  }

  KOKKOS_INLINE_FUNCTION
  void operator()( size_type iwork, value_type & dst ) const
  {
    dst.value[0] += 1;
    dst.value[1] += iwork + 1;
    dst.value[2] += nwork - iwork;
  }
};

template< class DeviceType >
class ReduceFunctorFinal : public ReduceFunctor< long, DeviceType > {
public:
  typedef typename ReduceFunctor< long, DeviceType >::value_type value_type;

  KOKKOS_INLINE_FUNCTION
  ReduceFunctorFinal( const size_t n )
    : ReduceFunctor< long, DeviceType >( n ) {}

  KOKKOS_INLINE_FUNCTION
  void final( value_type & dst ) const
  {
    dst.value[0] = -dst.value[0];
    dst.value[1] = -dst.value[1];
    dst.value[2] = -dst.value[2];
  }
};

template< typename ScalarType, class DeviceType >
class RuntimeReduceFunctor
{
public:
  // Required for functor:
  typedef DeviceType  execution_space;
  typedef ScalarType  value_type[];
  const unsigned      value_count;

  // Unit test details:

  typedef typename execution_space::size_type size_type;

  const size_type     nwork;

  RuntimeReduceFunctor( const size_type arg_nwork,
                        const size_type arg_count )
    : value_count( arg_count )
    , nwork( arg_nwork ) {}

  KOKKOS_INLINE_FUNCTION
  void init( ScalarType dst[] ) const
  {
    for ( unsigned i = 0; i < value_count; ++i ) dst[i] = 0;
  }

  KOKKOS_INLINE_FUNCTION
  void join( volatile ScalarType dst[],
             const volatile ScalarType src[] ) const
  {
    for ( unsigned i = 0; i < value_count; ++i ) dst[i] += src[i];
  }

  KOKKOS_INLINE_FUNCTION
  void operator()( size_type iwork, ScalarType dst[] ) const
  {
    const size_type tmp[3] = { 1, iwork + 1, nwork - iwork };

    for ( size_type i = 0; i < value_count; ++i ) {
      dst[i] += tmp[ i % 3 ];
    }
  }
};

template< typename ScalarType, class DeviceType >
class RuntimeReduceMinMax
{
public:
  // Required for functor:
  typedef DeviceType  execution_space;
  typedef ScalarType  value_type[];
  const unsigned      value_count;

  // Unit test details:

  typedef typename execution_space::size_type size_type;

  const size_type     nwork;
  const ScalarType    amin;
  const ScalarType    amax;

  RuntimeReduceMinMax( const size_type arg_nwork,
                       const size_type arg_count )
    : value_count( arg_count )
    , nwork( arg_nwork )
    , amin( std::numeric_limits< ScalarType >::min() )
    , amax( std::numeric_limits< ScalarType >::max() )
    {}

  KOKKOS_INLINE_FUNCTION
  void init( ScalarType dst[] ) const
  {
    for ( unsigned i = 0; i < value_count; ++i ) {
      dst[i] = i % 2 ? amax : amin;
    }
  }

  KOKKOS_INLINE_FUNCTION
  void join( volatile ScalarType dst[],
             const volatile ScalarType src[] ) const
  {
    for ( unsigned i = 0; i < value_count; ++i ) {
      dst[i] = i % 2 ? ( dst[i] < src[i] ? dst[i] : src[i] )  // min
                     : ( dst[i] > src[i] ? dst[i] : src[i] ); // max
    }
  }

  KOKKOS_INLINE_FUNCTION
  void operator()( size_type iwork, ScalarType dst[] ) const
  {
    const ScalarType tmp[2] = { ScalarType( iwork + 1 )
                              , ScalarType( nwork - iwork ) };

    for ( size_type i = 0; i < value_count; ++i ) {
      dst[i] = i % 2 ? ( dst[i] < tmp[i % 2] ? dst[i] : tmp[i % 2] )
                     : ( dst[i] > tmp[i % 2] ? dst[i] : tmp[i % 2] );
    }
  }
};

template< class DeviceType >
class RuntimeReduceFunctorFinal : public RuntimeReduceFunctor< long, DeviceType > {
public:
  typedef RuntimeReduceFunctor< long, DeviceType > base_type;
  typedef typename base_type::value_type value_type;
  typedef long scalar_type;

  RuntimeReduceFunctorFinal( const size_t theNwork, const size_t count )
    : base_type( theNwork, count ) {}

  KOKKOS_INLINE_FUNCTION
  void final( value_type dst ) const
  {
    for ( unsigned i = 0; i < base_type::value_count; ++i ) {
      dst[i] = -dst[i];
    }
  }
};


namespace {

template< typename ScalarType, class DeviceType >
class TestReduce
{
public:
  typedef DeviceType execution_space;
  typedef typename execution_space::size_type size_type;

  TestReduce( const size_type & nwork )
  {
    run_test( nwork );
    run_test_final( nwork );
  }

  void run_test( const size_type & nwork )
  {
    typedef Test::ReduceFunctor< ScalarType, execution_space > functor_type;
    typedef typename functor_type::value_type value_type;

    enum { Count = 3 };
    enum { Repeat = 100 };

    value_type result[ Repeat ];

    const unsigned long nw   = nwork;
    const unsigned long nsum = nw % 2 ? nw * ( ( nw + 1 ) / 2 )
                                      : ( nw / 2 ) * ( nw + 1 );

    for ( unsigned i = 0; i < Repeat; ++i ) {
      Kokkos::parallel_reduce( nwork, functor_type( nwork ), result[i] );
    }

    for ( unsigned i = 0; i < Repeat; ++i ) {
      for ( unsigned j = 0; j < Count; ++j ) {
        const unsigned long correct = 0 == j % 3 ? nw : nsum;
        ASSERT_EQ( (ScalarType) correct, result[i].value[j] );
      }
    }
  }

  void run_test_final( const size_type & nwork )
  {
    typedef Test::ReduceFunctorFinal< execution_space > functor_type;
    typedef typename functor_type::value_type value_type;

    enum { Count = 3 };
    enum { Repeat = 100 };

    value_type result[ Repeat ];

    const unsigned long nw   = nwork;
    const unsigned long nsum = nw % 2 ? nw * ( ( nw + 1 ) / 2 )
                                      : ( nw / 2 ) * ( nw + 1 );

    for ( unsigned i = 0; i < Repeat; ++i ) {
      if ( i % 2 == 0 ) {
        Kokkos::parallel_reduce( nwork, functor_type( nwork ), result[i] );
      }
      else {
        Kokkos::parallel_reduce( "Reduce", nwork, functor_type( nwork ), result[i] );
      }
    }

    for ( unsigned i = 0; i < Repeat; ++i ) {
      for ( unsigned j = 0; j < Count; ++j ) {
        const unsigned long correct = 0 == j % 3 ? nw : nsum;
        ASSERT_EQ( (ScalarType) correct, -result[i].value[j] );
      }
    }
  }
};

template< typename ScalarType, class DeviceType >
class TestReduceDynamic
{
public:
  typedef DeviceType execution_space;
  typedef typename execution_space::size_type size_type;

  TestReduceDynamic( const size_type nwork )
  {
    run_test_dynamic( nwork );
    run_test_dynamic_minmax( nwork );
    run_test_dynamic_final( nwork );
  }

  void run_test_dynamic( const size_type nwork )
  {
    typedef Test::RuntimeReduceFunctor< ScalarType, execution_space > functor_type;

    enum { Count = 3 };
    enum { Repeat = 100 };

    ScalarType result[ Repeat ][ Count ];

    const unsigned long nw   = nwork;
    const unsigned long nsum = nw % 2 ? nw * ( ( nw + 1 ) / 2 )
                                      : ( nw / 2 ) * ( nw + 1 );

    for ( unsigned i = 0; i < Repeat; ++i ) {
      if ( i % 2 == 0 ) {
        Kokkos::parallel_reduce( nwork, functor_type( nwork, Count ), result[i] );
      }
      else {
        Kokkos::parallel_reduce( "Reduce", nwork, functor_type( nwork, Count ), result[i] );
      }
    }

    for ( unsigned i = 0; i < Repeat; ++i ) {
      for ( unsigned j = 0; j < Count; ++j ) {
        const unsigned long correct = 0 == j % 3 ? nw : nsum;
        ASSERT_EQ( (ScalarType) correct, result[i][j] );
      }
    }
  }

  void run_test_dynamic_minmax( const size_type nwork )
  {
    typedef Test::RuntimeReduceMinMax< ScalarType, execution_space > functor_type;

    enum { Count = 2 };
    enum { Repeat = 100 };

    ScalarType result[ Repeat ][ Count ];

    for ( unsigned i = 0; i < Repeat; ++i ) {
      if ( i % 2 == 0 ) {
        Kokkos::parallel_reduce( nwork, functor_type( nwork, Count ), result[i] );
      }
      else {
        Kokkos::parallel_reduce( "Reduce", nwork, functor_type( nwork, Count ), result[i] );
      }
    }

    for ( unsigned i = 0; i < Repeat; ++i ) {
      for ( unsigned j = 0; j < Count; ++j ) {
        if ( nwork == 0 )
        {
          ScalarType amin( std::numeric_limits< ScalarType >::min() );
          ScalarType amax( std::numeric_limits< ScalarType >::max() );
          const ScalarType correct = ( j % 2 ) ? amax : amin;
          ASSERT_EQ( (ScalarType) correct, result[i][j] );
        }
        else {
          const unsigned long correct = j % 2 ? 1 : nwork;
          ASSERT_EQ( (ScalarType) correct, result[i][j] );
        }
      }
    }
  }

  void run_test_dynamic_final( const size_type nwork )
  {
    typedef Test::RuntimeReduceFunctorFinal< execution_space > functor_type;

    enum { Count = 3 };
    enum { Repeat = 100 };

    typename functor_type::scalar_type result[ Repeat ][ Count ];

    const unsigned long nw   = nwork;
    const unsigned long nsum = nw % 2 ? nw * ( ( nw + 1 ) / 2 )
                                      : ( nw / 2 ) * ( nw + 1 );

    for ( unsigned i = 0; i < Repeat; ++i ) {
      if ( i % 2 == 0 ) {
        Kokkos::parallel_reduce( nwork, functor_type( nwork, Count ), result[i] );
      }
      else {
        Kokkos::parallel_reduce( "TestKernelReduce", nwork, functor_type( nwork, Count ), result[i] );
      }

    }

    for ( unsigned i = 0; i < Repeat; ++i ) {
      for ( unsigned j = 0; j < Count; ++j ) {
        const unsigned long correct = 0 == j % 3 ? nw : nsum;
        ASSERT_EQ( (ScalarType) correct, -result[i][j] );
      }
    }
  }
};

template< typename ScalarType, class DeviceType >
class TestReduceDynamicView
{
public:
  typedef DeviceType execution_space;
  typedef typename execution_space::size_type size_type;

  TestReduceDynamicView( const size_type nwork )
  {
    run_test_dynamic_view( nwork );
  }

  void run_test_dynamic_view( const size_type nwork )
  {
    typedef Test::RuntimeReduceFunctor< ScalarType, execution_space > functor_type;

    typedef Kokkos::View< ScalarType*, DeviceType > result_type;
    typedef typename result_type::HostMirror result_host_type;

    const unsigned CountLimit = 23;

    const unsigned long nw   = nwork;
    const unsigned long nsum = nw % 2 ? nw * ( ( nw + 1 ) / 2 )
                                      : ( nw / 2 ) * ( nw + 1 );

    for ( unsigned count = 0; count < CountLimit; ++count ) {

      result_type result( "result", count );
      result_host_type host_result = Kokkos::create_mirror( result );

      // Test result to host pointer:

      std::string str( "TestKernelReduce" );
      if ( count % 2 == 0 ) {
        Kokkos::parallel_reduce( nw, functor_type( nw, count ), host_result.data() );
      }
      else {
        Kokkos::parallel_reduce( str, nw, functor_type( nw, count ), host_result.data() );
      }

      for ( unsigned j = 0; j < count; ++j ) {
        const unsigned long correct = 0 == j % 3 ? nw : nsum;
        ASSERT_EQ( host_result( j ), (ScalarType) correct );
        host_result( j ) = 0;
      }
    }
  }
};

} // namespace


TEST_F( TEST_CATEGORY, long_reduce )
{
  TestReduce< long, TEST_EXECSPACE >( 0 );
  TestReduce< long, TEST_EXECSPACE >( 1000000 );
}

TEST_F( TEST_CATEGORY, double_reduce )
{
  TestReduce< double, TEST_EXECSPACE >( 0 );
  TestReduce< double, TEST_EXECSPACE >( 1000000 );
}

TEST_F( TEST_CATEGORY, long_reduce_dynamic )
{
  TestReduceDynamic< long, TEST_EXECSPACE >( 0 );
  TestReduceDynamic< long, TEST_EXECSPACE >( 1000000 );
}

TEST_F( TEST_CATEGORY, double_reduce_dynamic )
{
  TestReduceDynamic< double, TEST_EXECSPACE >( 0 );
  TestReduceDynamic< double, TEST_EXECSPACE >( 1000000 );
}

TEST_F( TEST_CATEGORY, long_reduce_dynamic_view )
{
  TestReduceDynamicView< long, TEST_EXECSPACE >( 0 );
  TestReduceDynamicView< long, TEST_EXECSPACE >( 1000000 );
}

} // namespace Test