fp16 implementation, TODO deallocate in LayerWgs

src/kernels/convert.cu

@@ -0,0 +1,21 @@
+#include "kernels.h"
+
+__global__
+void float2half_device(float *input, __half *output, int size) {
+
+    int i = blockDim.x*blockIdx.x + threadIdx.x;
+
+    if(i<size) {    
+        output[i] = __float2half(input[i]);
+    }
+}
+
+
+void float2half(float* srcData, __half *dstData, int size, const cudaStream_t stream)
+{
+    int blocks = (size+255)/256;
+    int threads = 256;
+    
+    float2half_device<<<blocks, threads, 0, stream>>>(srcData, dstData, size);
+    cudaDeviceSynchronize();
+}