From 23da8daa7408ca7c59781b9e7b93d07e2382bb39 Mon Sep 17 00:00:00 2001
From: Denis Demidov <dennis.demidov@gmail.com>
Date: Tue, 17 May 2016 11:37:46 +0300
Subject: [PATCH] Get rid of fusion::vector_tie in implementation of
 generator::kernel

Fixes #206
---
 examples/symbolic.cpp |  8 +++++++-
 vexcl/generator.hpp   | 28 +++++++++++-----------------
 2 files changed, 18 insertions(+), 18 deletions(-)

diff --git a/examples/symbolic.cpp b/examples/symbolic.cpp
index 9c1130715..758a9d368 100644
--- a/examples/symbolic.cpp
+++ b/examples/symbolic.cpp
@@ -89,6 +89,8 @@ int main( int argc , char **argv )
     sym_stepper.do_step(std::ref(sys), sym_S, 0, dt);
 
     auto kernel = vex::generator::build_kernel(ctx, "lorenz", body.str(),
+            sym_S[0], sym_S[1], sym_S[2], sym_R,
+            sym_S[0], sym_S[1], sym_S[2], sym_R,
             sym_S[0], sym_S[1], sym_S[2], sym_R
             );
 
@@ -109,7 +111,11 @@ int main( int argc , char **argv )
 
     // Integration loop:
     for(value_type t = 0; t < t_max; t += dt)
-        kernel(X, Y, Z, R);
+        kernel(
+                X, Y, Z, R,
+                X, Y, Z, R,
+                X, Y, Z, R
+                );
 
     std::vector< value_type > result( n );
     vex::copy( X , result );
diff --git a/vexcl/generator.hpp b/vexcl/generator.hpp
index 48e51b715..14a948173 100644
--- a/vexcl/generator.hpp
+++ b/vexcl/generator.hpp
@@ -577,10 +577,10 @@ class kernel {
 
 #ifndef BOOST_NO_VARIADIC_TEMPLATES
         /// Launches the kernel with the provided parameters.
-        template <class... Param>
-        void operator()(const Param&... param) {
-            boost::fusion::for_each(boost::fusion::vector_tie(param...), push_args(*this));
-            (*this)();
+        template <class Head, class... Tail>
+        void operator()(const Head &head, const Tail&... tail) {
+            push_arg(head);
+            (*this)(tail...);
         }
 #else
 
@@ -600,16 +600,13 @@ BOOST_PP_REPEAT_FROM_TO(1, VEXCL_MAX_ARITY, VEXCL_FUNCALL_OPERATOR, ~)
 
 #endif
 
-        struct add_params {
-            kernel &K;
-
-            add_params(kernel &K) : K(K) {}
+        static void add_params(kernel &K) {}
 
-            template <class T>
-            void operator()(const T &v) const {
-                K.add_param(v);
-            }
-        };
+        template <class Head, class... Tail>
+        static void add_params(kernel &K, const Head &head, const Tail&... tail) {
+            K.add_param(head);
+            add_params(K, tail...);
+        }
     private:
         std::vector<backend::command_queue> queue;
         std::string name;
@@ -674,10 +671,7 @@ kernel build_kernel(
         )
 {
     kernel K(queue, name);
-    boost::fusion::for_each(
-            boost::fusion::vector_tie(args...),
-            kernel::add_params(K)
-            );
+    kernel::add_params(K, args...);
     K.build(body);
     return K;
 }