One more fix of reduction in distributed vector.

src/TNL/Containers/Expressions/DistributedVerticalOperations.h

@@ -39,7 +39,7 @@ auto DistributedExpressionArgMin( const Expression& expression )
 {
    using RealType = std::decay_t< decltype( expression[0] ) >;
    using IndexType = typename Expression::IndexType;
-   using ResultType = std::pair< IndexType, RealType >;
+   using ResultType = std::pair< RealType, IndexType >;
    using CommunicatorType = typename Expression::CommunicatorType;
 
    ResultType result( -1, std::numeric_limits< RealType >::max() );
@@ -48,7 +48,7 @@ auto DistributedExpressionArgMin( const Expression& expression )
       // compute local argMin
       ResultType localResult = ExpressionArgMin( expression.getConstLocalView() );
       // transform local index to global index
-      localResult.first += expression.getLocalRange().getBegin();
+      localResult.second += expression.getLocalRange().getBegin();
 
       // scatter local result to all processes and gather their results
       const int nproc = CommunicatorType::GetSize( group );
@@ -61,7 +61,7 @@ auto DistributedExpressionArgMin( const Expression& expression )
 
       // reduce the gathered data
       const auto* _data = gatheredResults;  // workaround for nvcc which does not allow to capture variable-length arrays (even in pure host code!)
-      auto fetch = [_data] ( IndexType i ) { return _data[ i ].second; };
+      auto fetch = [_data] ( IndexType i ) { return _data[ i ].first; };
       auto reduction = [] ( RealType& a, const RealType& b, IndexType& aIdx, const IndexType& bIdx ) {
          if( a > b ) {
             a = b;
@@ -71,7 +71,7 @@ auto DistributedExpressionArgMin( const Expression& expression )
             aIdx = bIdx;
       };
       result = Algorithms::Reduction< Devices::Host >::reduceWithArgument( (IndexType) 0, (IndexType) nproc, reduction, fetch, std::numeric_limits< RealType >::max() );
-      result.first = gatheredResults[ result.first ].first;
+      result.second = gatheredResults[ result.second ].second;
    }
    return result;
 }
@@ -96,7 +96,7 @@ auto DistributedExpressionArgMax( const Expression& expression )
 {
    using RealType = std::decay_t< decltype( expression[0] ) >;
    using IndexType = typename Expression::IndexType;
-   using ResultType = std::pair< IndexType, RealType >;
+   using ResultType = std::pair< RealType, IndexType >;
    using CommunicatorType = typename Expression::CommunicatorType;
 
    ResultType result( -1, std::numeric_limits< RealType >::lowest() );
@@ -105,7 +105,7 @@ auto DistributedExpressionArgMax( const Expression& expression )
       // compute local argMax
       ResultType localResult = ExpressionArgMax( expression.getConstLocalView() );
       // transform local index to global index
-      localResult.first += expression.getLocalRange().getBegin();
+      localResult.second += expression.getLocalRange().getBegin();
 
       // scatter local result to all processes and gather their results
       const int nproc = CommunicatorType::GetSize( group );
@@ -118,7 +118,7 @@ auto DistributedExpressionArgMax( const Expression& expression )
 
       // reduce the gathered data
       const auto* _data = gatheredResults;  // workaround for nvcc which does not allow to capture variable-length arrays (even in pure host code!)
-      auto fetch = [_data] ( IndexType i ) { return _data[ i ].second; };
+      auto fetch = [_data] ( IndexType i ) { return _data[ i ].first; };
       auto reduction = [] ( RealType& a, const RealType& b, IndexType& aIdx, const IndexType& bIdx ) {
          if( a < b ) {
             a = b;
@@ -128,7 +128,7 @@ auto DistributedExpressionArgMax( const Expression& expression )
             aIdx = bIdx;
       };
       result = Algorithms::Reduction< Devices::Host >::reduceWithArgument( ( IndexType ) 0, (IndexType) nproc, reduction, fetch, std::numeric_limits< RealType >::lowest() );
-      result.first = gatheredResults[ result.first ].first;
+      result.second = gatheredResults[ result.second ].second;
    }
    return result;
 }