diff --git a/examples_cuda/rt/Makefile_gpu b/examples_cuda/rt/Makefile_gpu
index 2eba1da2..9fbd67b0 100644
--- a/examples_cuda/rt/Makefile_gpu
+++ b/examples_cuda/rt/Makefile_gpu
@@ -1,5 +1,5 @@
 PROG=rt_cu
-ISPC_SRC=rt1.ispc
+ISPC_SRC=rt.ispc
 CXX_SRC=rt_cu.cpp 
 
 CXX=g++
diff --git a/examples_ptx/common_gpu.mk b/examples_ptx/common_gpu.mk
index 79e3b47b..cd0ef686 100644
--- a/examples_ptx/common_gpu.mk
+++ b/examples_ptx/common_gpu.mk
@@ -1,7 +1,7 @@
 NVCC_SRC=../nvcc_helpers.cu
 NVCC_OBJS=objs_gpu/nvcc_helpers_nvcc.o
 #
-CXX=g++
+CXX=g++ -ffast-math
 CXXFLAGS=-O3 -I$(CUDATK)/include -Iobjs_gpu/ -D_CUDA_
 #
 NVCC=nvcc
diff --git a/examples_ptx/rt/rt.ispc b/examples_ptx/rt/rt.ispc
index b9dc930b..c707f530 100644
--- a/examples_ptx/rt/rt.ispc
+++ b/examples_ptx/rt/rt.ispc
@@ -31,7 +31,11 @@
    SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.  
 */
 
+#if 1
+typedef int bool_t;
+#else
 typedef bool bool_t;
+#endif
 typedef float<3> float3;
 
 #if 0