add pre-execution function to operation classes

src/include/multi_array_operation.cc.h

@@ -76,6 +76,27 @@ namespace MultiArrayTools
 	    (THIS(), inds...);
     }
 
+    template <typename T, class OperationClass>
+    template <class... Indices>
+    auto OperationBase<T,OperationClass>::p(const std::shared_ptr<Indices>&... inds) const
+	-> ConstOperationRoot<T,typename Indices::RangeType...>
+    {
+	auto ma = std::make_shared<MultiArray<T,typename Indices::RangeType...>>
+	    (inds->range()... , static_cast<T>(0));
+	(*ma)(inds...) = THIS();
+	return ConstOperationRoot<T,typename Indices::RangeType...>(ma, inds...);
+    }
+
+    template <typename T, class OperationClass>
+    template <class... Indices>
+    auto OperationBase<T,OperationClass>::operator()(const std::shared_ptr<Indices>&... inds) const
+	-> MultiArray<T,typename Indices::RangeType...>
+    {
+	MultiArray<T,typename Indices::RangeType...> out(inds->range()... , static_cast<T>(0));
+	out(inds...) = THIS();
+	return out;
+    }
+
     template <typename T, class OperationClass>
     template <typename R, class... Args>
     auto OperationBase<T,OperationClass>::a(const std::shared_ptr<function<R,T,typename Args::value_type...>>& ll,

src/include/multi_array_operation.h

@@ -61,6 +61,14 @@ namespace MultiArrayTools
 	auto slc(const std::shared_ptr<Indices>&... inds) const
 	    -> SliceContraction<T,OperationClass,Indices...>;
 
+	template <class... Indices>
+	auto p(const std::shared_ptr<Indices>&... inds) const
+	    -> ConstOperationRoot<T,typename Indices::RangeType...>;
+
+	template <class... Indices>
+	auto operator()(const std::shared_ptr<Indices>&... inds) const
+	    -> MultiArray<T,typename Indices::RangeType...>;
+
         template <typename R, class... Args> // Args = Operation Classes
         auto a(const std::shared_ptr<function<R,T,typename Args::value_type...>>& ll, const Args&... args) const
             -> Operation<R,function<R,T,typename Args::value_type...>,OperationClass, Args...>;

src/include/ranges/dynamic_range.h

@@ -67,6 +67,15 @@ namespace MultiArrayTools
 	//virtual size_t posAt(const U& metaPos) const = 0;
 
 	//virtual bool isMeta(const U& metaPos) const = 0;
+	inline AbstractIW& at(const std::string smeta)
+	{
+	    for((*this) = 0; this->pos() != this->max(); ++(*this)){
+		if(this->stringMeta() == smeta){
+		    break;
+		}
+	    }
+	    return *this;
+	}
     };
     
     template <class ExpressionCollection>

src/tests/op_unit_test.cc

@@ -565,7 +565,7 @@ namespace {
 	auto i1 = MAT::getIndex( mr1ptr );
 	auto i2 = MAT::getIndex( sr4ptr );
 	
-	res(i1,i2) = ( ma1(i1) + ma2(i2) ) - ma3(i2);
+	res(i1,i2) = ( ma1(i1) + ma2(i2) ).p(i1,i2) - ma3(i2);
 
 	EXPECT_EQ( xround( res.at(mkt(mkt('1','a'),'A')) ), xround(0.353 + 8.870 - 1.470)  );
 	EXPECT_EQ( xround( res.at(mkt(mkt('1','a'),'B')) ), xround(0.353 + 4.790 - 2.210)  );