From b88f62d50e097b2385cb903c88fbf44ac32a333f Mon Sep 17 00:00:00 2001
From: Olivier Parcollet <olivier.parcollet@cea.fr>
Date: Wed, 28 Aug 2013 11:15:26 +0200
Subject: [PATCH] arrays: details while writing doc

- add factories for matrices
- add make_immutablef from a lambda
- details
---
 test/triqs/arrays/make_immutables.cpp       |  6 ++++
 triqs/arrays/algorithms.hpp                 | 20 +++---------
 triqs/arrays/impl/indexmap_storage_pair.hpp |  2 ++
 triqs/arrays/indexmaps/range.hpp            |  2 ++
 triqs/arrays/make_immutable_array.hpp       | 36 ++++++++++++++++++---
 triqs/arrays/matrix.hpp                     | 15 +++++++++
 6 files changed, 60 insertions(+), 21 deletions(-)

diff --git a/test/triqs/arrays/make_immutables.cpp b/test/triqs/arrays/make_immutables.cpp
index dd93af3e..4421e146 100644
--- a/test/triqs/arrays/make_immutables.cpp
+++ b/test/triqs/arrays/make_immutables.cpp
@@ -36,5 +36,11 @@ int main(int argc, char **argv) {
  
  TEST( (tqa::array<int,2>(tqa::make_immutable_array( i_ + j_, i_= range(0,2), j_=range(0,2)))));
 
+ // or if you prefer using a lambda...
+ auto b = make_immutable_array ( [](int i, int j) { return i-j;}, range (0,2), range(0,2));
+
+ std::cerr << "b = " << b                  << std::endl;
+ std::cerr << "b = " << tqa::array<double,2>(b) << std::endl;
+
  return 0;
 }
diff --git a/triqs/arrays/algorithms.hpp b/triqs/arrays/algorithms.hpp
index 9059d0ae..8779c6ca 100644
--- a/triqs/arrays/algorithms.hpp
+++ b/triqs/arrays/algorithms.hpp
@@ -26,8 +26,6 @@
 #include "./functional/fold.hpp"
 #include <boost/preprocessor/repetition/repeat_from_to.hpp>
 
-#define TRIQS_FIX_CLANG30_linux
-
 namespace triqs { namespace arrays {
 
  // get_first_element(a) returns .. the first element, i.e. a(0,0,0...)
@@ -41,22 +39,14 @@ namespace triqs { namespace arrays {
 
  template<class A>
   typename A::value_type max_element(A const &a) { 
-#ifdef TRIQS_FIX_CLANG30_linux
-   typedef typename A::value_type const & T;
-   return fold ( static_cast<T(*)(T,T)>(std::max<T>))  ( a, get_first_element(a)); 
-#else  
-   return fold ( std::max<typename A::value_type const & >)  ( a, get_first_element(a)); 
-#endif
+   //typedef typename A::value_type const & T; return fold ( static_cast<T(*)(T,T)>(std::max<T>))  ( a, get_first_element(a)); 
+   return fold (std::max<typename A::value_type const & >)  (a, get_first_element(a)); 
   }
 
  template<class A>
   typename A::value_type min_element(A const &a) { 
-#ifdef TRIQS_FIX_CLANG30_linux
- typedef typename A::value_type const & T;
-   return fold ( static_cast<T(*)(T,T)>(std::min<T>))  ( a, get_first_element(a)); 
-#else 
-   return fold ( std::min<typename A::value_type const & >)  ( a,  get_first_element(a)); 
-#endif
+   // typedef typename A::value_type const & T; return fold ( static_cast<T(*)(T,T)>(std::min<T>))  ( a, get_first_element(a)); 
+   return fold (std::min<typename A::value_type const & >)  (a, get_first_element(a)); 
   }
 
  template <class A>
@@ -65,9 +55,7 @@ namespace triqs { namespace arrays {
  template <class A>
   typename A::value_type prod(A const & a) { return fold ( std::multiplies<typename A::value_type>())  (a,1); }
 
-
 }}//namespace triqs::arrays 
-
 #endif
 
 
diff --git a/triqs/arrays/impl/indexmap_storage_pair.hpp b/triqs/arrays/impl/indexmap_storage_pair.hpp
index 0628c602..470802be 100644
--- a/triqs/arrays/impl/indexmap_storage_pair.hpp
+++ b/triqs/arrays/impl/indexmap_storage_pair.hpp
@@ -63,6 +63,8 @@ namespace triqs { namespace arrays {
     typedef IndexMapType indexmap_type;
     static constexpr unsigned int rank = IndexMapType::domain_type::rank;
     static constexpr ull_t opt_flags = OptionFlags;
+    static constexpr ull_t traversal_order = TraversalOrder;
+   
    protected:
 
     indexmap_type indexmap_;
diff --git a/triqs/arrays/indexmaps/range.hpp b/triqs/arrays/indexmaps/range.hpp
index bb85a4c7..ca58576f 100644
--- a/triqs/arrays/indexmaps/range.hpp
+++ b/triqs/arrays/indexmaps/range.hpp
@@ -30,6 +30,8 @@ namespace triqs { namespace arrays {
   std::ptrdiff_t first_, last_, step_;
   public:
 
+  typedef std::ptrdiff_t index_type;
+
   range():first_(0),last_(-1),step_(1) {} // i.e. all
   range(const range& r):first_(r.first_), last_(r.last_), step_(r.step_) {}
   range(std::ptrdiff_t first__, std::ptrdiff_t last__, std::ptrdiff_t step__=1):first_(first__), last_(last__), step_(step__) {}
diff --git a/triqs/arrays/make_immutable_array.hpp b/triqs/arrays/make_immutable_array.hpp
index 8b7aac8b..4d1df7f4 100644
--- a/triqs/arrays/make_immutable_array.hpp
+++ b/triqs/arrays/make_immutable_array.hpp
@@ -21,20 +21,22 @@
 #ifndef TRIQS_ARRAYS_MAKE_IMMUTABLE_ARRAY_H
 #define TRIQS_ARRAYS_MAKE_IMMUTABLE_ARRAY_H
 #include "./array.hpp"
+#include "../utility/tuple_tools.hpp"
+
 namespace triqs { namespace arrays { 
 
  template<typename Expr, int ... ph>
-  class immutable_array_impl : TRIQS_CONCEPT_TAG_NAME(ImmutableCuboidArray) { 
+  class immutable_array_expr_impl : TRIQS_CONCEPT_TAG_NAME(ImmutableCuboidArray) { 
    template<int I> struct _si { typedef size_t type;};
    public : 
-    immutable_array_impl(Expr e_, clef::pair<ph,range> ... p): 
+    immutable_array_expr_impl(Expr e_, clef::pair<ph,range> ... p): 
      f(clef::make_function(e_, clef::placeholder<ph>()...)), dom_(make_shape(p.rhs().size()...)) {};
     typedef typename triqs::clef::result_of::make_function<Expr,clef::placeholder<ph>... >::type function_type;
     typedef typename std::result_of<function_type(typename _si<ph>::type...)>::type value_type;
     typedef indexmaps::cuboid::domain_t<sizeof...(ph)> domain_type;
     domain_type domain() const { return dom_;} 
     template<typename ... Args> value_type operator() (Args const &  ... args) const { return f(args...); } 
-    friend std::ostream & operator<<(std::ostream & out, immutable_array_impl const & x){return out<<" immutable_array on domain : "<<x.domain();}
+    friend std::ostream & operator<<(std::ostream & out, immutable_array_expr_impl const & x){return out<<" immutable_array on domain : "<<x.domain();}
    protected:
     function_type f;
     domain_type dom_;
@@ -47,10 +49,34 @@ namespace triqs { namespace arrays {
   * \return A lazy object implementing the ImmutableCuboidArray concept with the domain built from the ranges. 
   */
  template<typename Expr, int ... ph>
-  immutable_array_impl<Expr,ph...> make_immutable_array( Expr const & expr, clef::pair<ph,range> ... p) {
-   return immutable_array_impl<Expr,ph...> (expr, p...);
+  immutable_array_expr_impl<Expr,ph...> make_immutable_array( Expr const & expr, clef::pair<ph,range> ... p) {
+   return immutable_array_expr_impl<Expr,ph...> (expr, p...);
   }
 
+ // if ones prefers to use a function...
+
+ template<typename Function, typename ... Ranges>
+  class immutable_array_fun_impl : TRIQS_CONCEPT_TAG_NAME(ImmutableCuboidArray) { 
+   template<int I> struct _si { typedef size_t type;};
+   public : 
+   immutable_array_fun_impl(Function f, Ranges ... r) : f_(std::move(f)), dom_(make_shape(r.size()...)) {};
+   //typedef typename std::function<Function(typename Ranges::index_type...)>::result_type value_type;
+   typedef decltype( triqs::tuple::apply(std::declval<Function>(),std::make_tuple(typename Ranges::index_type()...))) value_type;
+   typedef indexmaps::cuboid::domain_t<sizeof...(Ranges)> domain_type;
+   domain_type domain() const { return dom_;} 
+   template<typename ... Args> value_type operator() (Args const &  ... args) const { return f_(args...); } 
+   friend std::ostream & operator<<(std::ostream & out, immutable_array_fun_impl const & x){return out<<" immutable_array on domain : "<<x.domain();}
+   protected:
+   Function f_;
+   domain_type dom_;
+  };
+
+ template<typename Function, typename ... Ranges>
+  immutable_array_fun_impl<Function,Ranges...> make_immutable_array(Function f, Ranges ... r) {
+   return immutable_array_fun_impl<Function,Ranges...> (std::move(f), r...);
+  }
+
+
 }}//namespace triqs::arrays
 #endif
 
diff --git a/triqs/arrays/matrix.hpp b/triqs/arrays/matrix.hpp
index 8eef4d4f..f7f61f96 100644
--- a/triqs/arrays/matrix.hpp
+++ b/triqs/arrays/matrix.hpp
@@ -193,6 +193,21 @@ namespace triqs { namespace arrays {
 #undef _IMPL_MATRIX_COMMON
 #undef IMPL_TYPE
 
+
+ template<typename ArrayType>
+  matrix_view<typename ArrayType::value_type, ArrayType::opt_flags, ArrayType::traversal_order>
+  make_matrix_view(ArrayType const & a) { 
+   static_assert(ArrayType::rank ==2, "make_matrix_view only works for array of rank 2");
+   return a;
+  }
+
+ template<typename ArrayType>
+  matrix<typename ArrayType::value_type, ArrayType::opt_flags, ArrayType::traversal_order>
+  make_matrix(ArrayType const & a) { 
+   static_assert(ArrayType::rank ==2, "make_matrix_view only works for array of rank 2");
+   return a;
+  }
+
 }}//namespace triqs::arrays
 
 // The std::swap is WRONG for a view because of the copy/move semantics of view.