Caffe nvcc编译问题：Unsupported gpu architecture

最近学习DSSD，从https://github.com/chengyangfu/caffe/tree/dssd下载源码后编译报错：Unsupported gpu architecture 'compute_20'，具体如下：

CXX src/caffe/util/db.cpp
CXX src/caffe/util/benchmark.cpp
CXX src/caffe/util/im2col.cpp
CXX src/caffe/util/math_functions.cpp
NVCC src/caffe/solvers/adagrad_solver.cu
nvcc fatal   : Unsupported gpu architecture 'compute_20'
make: *** [.build_release/cuda/src/caffe/solvers/adagrad_solver.o] Error 1
make: *** Waiting for unfinished jobs....

根据Makefile.config的注释：

# CUDA architecture setting: going with all of them.
# For CUDA < 6.0, comment the *_50 through *_61 lines for compatibility.
# For CUDA < 8.0, comment the *_60 and *_61 lines for compatibility.
# For CUDA >= 9.0, comment the *_20 and *_21 lines for compatibility.
CUDA_ARCH := -gencode arch=compute_20,code=sm_20 \
                -gencode arch=compute_20,code=sm_21 \
                -gencode arch=compute_30,code=sm_30 \
                -gencode arch=compute_35,code=sm_35 \
                -gencode arch=compute_50,code=sm_50 \
                -gencode arch=compute_52,code=sm_52 \
                -gencode arch=compute_60,code=sm_60 \
                -gencode arch=compute_61,code=sm_61 \
                -gencode arch=compute_61,code=compute_61

我的环境是cuda9.0，所以把如下两行注释：

-gencode arch=compute_20,code=sm_20 \
-gencode arch=compute_20,code=sm_21 \

之后问题解决。