Replace boost:circular_buffer with amgcl::circular_buffer

amgcl/solver/lgmres.hpp

@@ -70,8 +70,6 @@ THE SOFTWARE.
 #include <cmath>
 #include <tuple>
 
-#include <boost/circular_buffer.hpp>
-
 #include <amgcl/backend/interface.hpp>
 #include <amgcl/solver/detail/default_inner_product.hpp>
 #include <amgcl/solver/detail/givens_rotations.hpp>
@@ -413,8 +411,8 @@ class lgmres {
         std::shared_ptr<vector> r;
         mutable std::vector< std::shared_ptr<vector> > vs, ws;
         mutable std::vector< std::shared_ptr<vector> > outer_v_data, outer_Av_data;
-        mutable boost::circular_buffer< std::shared_ptr<vector> > outer_v;
-        mutable boost::circular_buffer< std::shared_ptr<vector> > outer_Av;
+        mutable circular_buffer< std::shared_ptr<vector> > outer_v;
+        mutable circular_buffer< std::shared_ptr<vector> > outer_Av;
 
 
         InnerProduct inner_product;

amgcl/util.hpp

@@ -221,6 +221,44 @@ class multi_array {
         }
 };
 
+template <class T>
+class circular_buffer {
+    public:
+        circular_buffer(size_t n) : start(0) {
+            buf.reserve(n);
+        }
+
+        size_t size() const {
+            return buf.size();
+        }
+
+        void push_back(const T &v) {
+            if (buf.size() < buf.capacity()) {
+                buf.push_back(v);
+            } else {
+                buf[start] = v;
+                start = (start + 1) % buf.capacity();
+            }
+        }
+
+        const T& operator[](size_t i) const {
+            return buf[(start + i) % buf.capacity()];
+        }
+
+        T& operator[](size_t i) {
+            return buf[(start + i) % buf.capacity()];
+        }
+
+        void clear() {
+            buf.clear();
+            start = 0;
+        }
+
+    private:
+        size_t start;
+        std::vector<T> buf;
+};
+
 namespace detail {
 
 inline const boost::property_tree::ptree& empty_ptree() {