Make the batcher and partition iterators usable

include/integratorxx/batch/spherical_micro_batcher.hpp

@@ -255,10 +255,10 @@ class SphericalMicroBatcher {
 
     using value_type        = 
       std::tuple<point_type,point_type,point_container,weight_container>;
-    using different_type    = size_t;
-    using pointer           = value_type*;
-    using reference         = value_type&;
-    using iterator_catagory = std::input_iterator_tag;
+    using difference_type   = std::ptrdiff_t;
+    using pointer           = void;
+    using reference         = value_type;
+    using iterator_category = std::input_iterator_tag;
 
     index_iterator idx_it;
     point_iterator  point_begin;
@@ -275,17 +275,18 @@ class SphericalMicroBatcher {
       return retval;
     }
 
-    iterator& operator+(int i) {
-      idx_it += i;
-      return *this;
-    } 
+    iterator operator+(difference_type i) const {
+      iterator copy = *this;
+      copy.idx_it += i;
+      return copy;
+    }
 
-    bool operator==( iterator other ){ return idx_it == other.idx_it; }
-    bool operator!=( iterator other ){ return !(*this == other);   }
+    bool operator==( const iterator& other ) const { return idx_it == other.idx_it; }
+    bool operator!=( const iterator& other ) const { return !(*this == other);   }
 
 
 
-    auto range() {
+    auto range() const {
 
       const auto idx      = *idx_it;
       const auto idx_next = *(idx_it+1);
@@ -302,7 +303,7 @@ class SphericalMicroBatcher {
 
     }
 
-    value_type operator*() {
+    value_type operator*() const {
 
       auto [npts,pb,pe,wb,we] = range();
       auto [box_lo, box_up]   = detail::get_box_bounds_points(pb, pe);
@@ -325,10 +326,10 @@ class SphericalMicroBatcher {
 
     using value_type        = 
       std::tuple<point_type,point_type,point_container,weight_container>;
-    using different_type    = size_t;
-    using pointer           = value_type*;
-    using reference         = value_type&;
-    using iterator_catagory = std::input_iterator_tag;
+    using difference_type   = std::ptrdiff_t;
+    using pointer           = void;
+    using reference         = value_type;
+    using iterator_category = std::input_iterator_tag;
 
     const_index_iterator idx_it;
     const_point_iterator  point_begin;
@@ -346,17 +347,18 @@ class SphericalMicroBatcher {
       return retval;
     }
 
-    const_iterator& operator+(int i) {
-      idx_it += i;
-      return *this;
-    } 
+    const_iterator operator+(difference_type i) const {
+      const_iterator copy = *this;
+      copy.idx_it += i;
+      return copy;
+    }
 
-    bool operator==( iterator other ){ return idx_it == other.idx_it; }
-    bool operator!=( iterator other ){ return !(*this == other);   }
+    bool operator==( const const_iterator& other ) const { return idx_it == other.idx_it; }
+    bool operator!=( const const_iterator& other ) const { return !(*this == other);   }
 
 
 
-    auto range() {
+    auto range() const {
 
       const auto idx      = *idx_it;
       const auto idx_next = *(idx_it+1);
@@ -373,7 +375,7 @@ class SphericalMicroBatcher {
 
     }
 
-    value_type operator*() {
+    value_type operator*() const {
 
       auto [npts,pb,pe,wb,we] = range();
       auto [box_lo, box_up]   = detail::get_box_bounds_points(pb, pe);
@@ -465,6 +467,9 @@ class SphericalMicroBatcher {
       quad_->weights().cbegin() );
   }
 
+  const_iterator begin() const { return cbegin(); }
+  const_iterator end()   const { return cend();   }
+
   typename iterator::value_type at( size_t i ) {
     if( i >= nbatches() )
       throw std::runtime_error("Index out of bounds");

include/integratorxx/composite_quadratures/pruned_spherical_quadrature.hpp

@@ -84,10 +84,10 @@ class RadialGridPartition {
     using index_range_type = std::pair<size_t,size_t>;
     using quad_type        = Quadrature<AngularQuad>;
     using value_type = std::pair<index_range_type, quad_type>;
-    using difference_type = size_t; 
-    using pointer           = value_type*;
-    using reference         = value_type&;
-    using iterator_catagory = std::input_iterator_tag;
+    using difference_type = std::ptrdiff_t;
+    using pointer           = void;
+    using reference         = value_type;
+    using iterator_category = std::input_iterator_tag;
 
     index_iterator idx_it;
     quad_iterator  quad_it;
@@ -98,21 +98,22 @@ class RadialGridPartition {
 
     rgp_iterator& operator++(){ idx_it++; quad_it++; return *this; }
     rgp_iterator  operator++(int) {
-      iterator retval = *this;
+      rgp_iterator retval = *this;
       ++(*this);
       return retval;
     }
 
-    rgp_iterator& operator+(int i) {
-      idx_it  += i;
-      quad_it += i;
-      return (*this);
+    rgp_iterator operator+(difference_type i) const {
+      rgp_iterator copy = *this;
+      copy.idx_it  += i;
+      copy.quad_it += i;
+      return copy;
     }
 
-    bool operator==(rgp_iterator other) const { 
+    bool operator==(const rgp_iterator& other) const { 
       return idx_it == other.idx_it && quad_it == other.quad_it; 
     }
-    bool operator!=(rgp_iterator other) const { return !(*this == other);   }
+    bool operator!=(const rgp_iterator& other) const { return !(*this == other);   }
 
     value_type operator*() {
       return std::make_pair( std::make_pair(*idx_it, *(idx_it+1)), *quad_it );

test/composite_quadratures.cxx

@@ -155,6 +155,26 @@ TEST_CASE( "Spherical Quadratures", "[sph-quad]" ) {
 
     CHECK( npts_c == npts );
 
+    // Iterating a const batcher: const_iterator compared against the
+    // non-const iterator type, so this could not previously compile.
+    npts_c = 0;
+    for( auto&& [box_lo, box_up, points_b, weights_b] : cbatcher ) {
+
+      auto npts_b = points_b.size();
+      CHECK( npts_b != 0 );
+      npts_c += npts_b;
+
+    }
+
+    CHECK( npts_c == npts );
+
+    npts_c = 0;
+    for( auto it = cbatcher.cbegin(); it != cbatcher.cend(); ++it ) {
+      npts_c += std::get<2>(*it).size();
+    }
+
+    CHECK( npts_c == npts );
+
     auto batcher_clone = batcher.clone();
     CHECK( &batcher.quadrature() != &batcher_clone.quadrature() );
     CHECK( batcher.npts() == batcher_clone.npts() );