Opencv + CUDA + 拓展代码 编译的记录

编译过Opencv3.0.0+CUDA 7.5+拓展库，随后编译了Opencv3.4+CUDA 9.2，编译源码首先要确定CUDA的版本以及opencv的版本是否对应，编译会出现unsupported gpu atch 'computer 2.0'的问题，字面理解意思似乎是不支持2.0的gpu架构

了解到设定 CUDA_GENERATION 是 Kepler就OK了，

CMAKE文件不怎么理解，大体上看得出来Kepler是大于3.0的计算机架构，正好定义了__cuda_arch_bin 

opencvdetectCUDA.cmake文件

set(__cuda_arch_ptx "")
  if(CUDA_GENERATION STREQUAL "Fermi")
    set(__cuda_arch_bin "2.0")
  elseif(CUDA_GENERATION STREQUAL "Kepler")
    set(__cuda_arch_bin "3.0 3.5 3.7")
  elseif(CUDA_GENERATION STREQUAL "Maxwell")
    set(__cuda_arch_bin "5.0 5.2")
  elseif(CUDA_GENERATION STREQUAL "Pascal")
    set(__cuda_arch_bin "6.0 6.1")
  elseif(CUDA_GENERATION STREQUAL "Volta")
    set(__cuda_arch_bin "7.0")
  elseif(CUDA_GENERATION STREQUAL "Auto")
    execute_process( COMMAND "${CUDA_NVCC_EXECUTABLE}" ${CUDA_NVCC_FLAGS} "${OpenCV_SOURCE_DIR}/cmake/checks/OpenCVDetectCudaArch.cu" "--run"
                     WORKING_DIRECTORY "${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeTmp/"
                     RESULT_VARIABLE _nvcc_res OUTPUT_VARIABLE _nvcc_out
                     ERROR_QUIET OUTPUT_STRIP_TRAILING_WHITESPACE)
    if(NOT _nvcc_res EQUAL 0)
      message(STATUS "Automatic detection of CUDA generation failed. Going to build for all known architectures.")
    else()
      set(__cuda_arch_bin "${_nvcc_out}")
      string(REPLACE "2.1" "2.1(2.0)" __cuda_arch_bin "${__cuda_arch_bin}")
    endif()
  endif()

Cmake出来的工程上 查询到arch=computer的记录，也就是对应于Kepler的几种版本的arch

opencvConfig.cmake 

# Version Compute Capability from which OpenCV has been compiled is remembered
set(OpenCV_COMPUTE_CAPABILITIES "-gencode;arch=compute_30,code=sm_30;-gencode;arch=compute_35,code=sm_35;-gencode;arch=compute_37,code=sm_37;-D_FORCE_INLINES")