最近因为这个错误折腾老长时间，重装caffe ssd好几次，没有什么作用，最后发现一个大佬解决这个问题
问题一：math_functions.cpp:250] Check failed: a <= b <0 vs -1.19209e-007>
解决：找到math_functions.cpp，找到在路径为~/caffe/src/caffe/util的math_functions.cpp，找到第250行出错的地方，双斜杠屏蔽，如下所示：最后重新在caffe路径下make -j8
问题二：Data layer prefetch queue empty
原因：因为如果注释掉 CHECK_LE(a, b) 会出现Data layer prefetch queue empty，不注释CHECK_LE(a, b) 会出现错误 a可能大于b，caffe_rng_uniform will get block, when bbox_width or bbox_height near 1.0 , (1 - bbox_width) will less than 0.f。
解决：找到在路径为~/caffe/src/caffe/util/sampler.cpp，在其中增加加粗黑体部分的代码
void SampleBBox(const Sampler& sampler, NormalizedBBox* sampled_bbox) {
// Get random scale.
CHECK_GE(sampler.max_scale(), sampler.min_scale());
CHECK_GT(sampler.min_scale(), 0.);
CHECK_LE(sampler.max_scale(), 1.);
float scale;
caffe_rng_uniform(1, sampler.min_scale(), sampler.max_scale(), &scale);
// Get random aspect ratio.
CHECK_GE(sampler.max_aspect_ratio(), sampler.min_aspect_ratio());
CHECK_GT(sampler.min_aspect_ratio(), 0.);
CHECK_LT(sampler.max_aspect_ratio(), FLT_MAX);
float aspect_ratio;
caffe_rng_uniform(1, sampler.min_aspect_ratio(), sampler.max_aspect_ratio(),
&aspect_ratio);
aspect_ratio = std::max(aspect_ratio, std::pow(scale, 2.));
aspect_ratio = std::min(aspect_ratio, 1 / std::pow(scale, 2.));
// Figure out bbox dimension.
float bbox_width = scale * sqrt(aspect_ratio);
float bbox_height = scale / sqrt(aspect_ratio);
if(bbox_width>=1.0){
bbox_width=1.0;
}
if(bbox_height>=1.0){
bbox_height=1.0;
}
// Figure out top left coordinates.
float w_off, h_off;
caffe_rng_uniform(1, 0.f, 1.0f - bbox_width, &w_off);
caffe_rng_uniform(1, 0.f, 1.0f - bbox_height, &h_off);
sampled_bbox->set_xmin(w_off);
sampled_bbox->set_ymin(h_off);
sampled_bbox->set_xmax(w_off + bbox_width);
sampled_bbox->set_ymax(h_off + bbox_height);
}
最后一定要记得重新在caffe路径下make -j8
原文链接：https://blog.csdn.net/jancis/java/article/details/102824091