Added documentation for cuda_wrappers (#18)

Author: fiza11

adaboost/utils/cuda_wrappers.hpp

@@ -13,17 +13,52 @@ namespace adaboost
             enum direction {HostToDevice, DeviceToHost};
             typedef cudaEvent_t cuda_event_t;
 
+            /*
+            * Used for allocating memory on the device.
+            *
+            * @param ptr Pointer to allocated device memory
+            * @param num_bytes Requested allocation size in bytes
+            * allocates num_bytes of linear memory on the device
+            */
             void cuda_malloc(void** ptr, unsigned num_bytes);
 
+            /*
+            * Used for copying data between host and device.
+            *
+            * @param ptr_1 Destination memory address
+            * @param ptr_2 Source memory address
+            * @param num_bytes Size in bytes to copy
+            * @param d Determines the direction of copying data
+            */
             void cuda_memcpy
             (void* ptr_1, void* ptr_2, unsigned num_bytes, direction d);
 
+            /*
+            * Used for creating an event object for the current device.
+            *
+            * @param event_ptr Newly created event
+            */
             void cuda_event_create(cuda_event_t* event_ptr);
 
+            /*
+            * Used for recording an event.
+            *
+            * @param event Event to record
+            */
             void cuda_event_record(cuda_event_t event);
 
+            /*
+            * Used for waiting for an event to complete.
+            *
+            * @param event Event to wait for
+            */
             void cuda_event_synchronize(cuda_event_t event);
 
+            /*
+            * Used for freeing memory on the device.
+            *
+            * @param ptr Device pointer to memory to free
+            */
             void cuda_free(void* ptr);
 
         } // namspace cuda