why descriptor doesn't work

[ghost]

Hello, first of all thank you very much for your contribution to the cuda version of the sift feature. now I am working on a project of image search. but when i use cudasift to extract the sift feature of both query image and database image, the sift feature of query image doesn't work. when i use CPU with vlfeat library to extract sift feature, I can achieve accuracy of 62.6%, but if I use cudasift, I can only achieve 6.2%。what is more strange is that if I just generate the 128-dimension descriptor using random methods, I can alse achieve 6%. So can I get some suggestion about this? thank you very much.