diff --git a/lib/simd/Grid_avx.h b/lib/simd/Grid_avx.h
index 73792f84..5c16dd71 100644
--- a/lib/simd/Grid_avx.h
+++ b/lib/simd/Grid_avx.h
@@ -470,13 +470,14 @@ namespace Optimization {
       return in;
     };
   };
-
+#define USE_FP16
   struct PrecisionChange {
     static inline __m256i StoH (__m256 a,__m256 b) {
+      __m256 h;
 #ifdef USE_FP16
       __m128i ha = _mm256_cvtps_ph(a,0);
       __m128i hb = _mm256_cvtps_ph(b,0);
-      __m256 h = _mm256_castps128_ps256(ha);
+      h = _mm256_castps128_ps256(ha);
       h = _mm256_insertf128_ps(h,hb,1);
 #else 
       assert(0);
diff --git a/lib/simd/Grid_avx512.h b/lib/simd/Grid_avx512.h
index 9156f113..ba054665 100644
--- a/lib/simd/Grid_avx512.h
+++ b/lib/simd/Grid_avx512.h
@@ -340,7 +340,7 @@ namespace Optimization {
     };
 
   };
-
+#define USE_FP16
   struct PrecisionChange {
     static inline __m512i StoH (__m512 a,__m512 b) {
       __m512i h;