各种BUG
1、安装了python3.6后ctrl+alt+T 无法打开终端，报错如下：
gnome-terminal
Traceback (most recent call last):
File "/usr/bin/gnome-terminal", line 9, in
from gi.repository import GLib, Gio
File "/usr/lib/python3/dist-packages/gi/__init__.py", line 42, in
from . import _gi
ImportError: cannot import name '_gi'
Error in sys.excepthook:
Traceback (most recent call last):
File "/usr/lib/python3/dist-packages/apport_python_hook.py", line 63, in apport_excepthook
from apport.fileutils import likely_packaged, get_recent_crashes
File "/usr/lib/python3/dist-packages/apport/__init__.py", line 5, in
from apport.report import Report
File "/usr/lib/python3/dist-packages/apport/report.py", line 30, in
import apport.fileutils
File "/usr/lib/python3/dist-packages/apport/fileutils.py", line 23, in
from apport.packaging_impl import impl as packaging
File "/usr/lib/python3/dist-packages/apport/packaging_impl.py", line 23, in
import apt
File "/usr/lib/python3/dist-packages/apt/__init__.py", line 23, in
import apt_pkg
ModuleNotFoundError: No module named 'apt_pkg'
Original exception was:
Traceback (most recent call last):
File "/usr/bin/gnome-terminal", line 9, in
from gi.repository import GLib, Gio
File "/usr/lib/python3/dist-packages/gi/__init__.py", line 42, in
from . import _gi
ImportError: cannot import name '_gi'
解决如下：
cd /usr/lib/python3/dist-packages/gi/
sudo cp _gi.cpython-35m-x86_64-linux-gnu.so _gi.cpython-36m-x86_64-linux-gnu.so
$ sudo cp _gi_cairo.cpython-35m-x86_64-linux-gnu.so _gi_cairo.cpython-36m-x86_64-linux-gnu.so
其实就是把3.5版本的文件改为3.6的，
参考链接：https://blog.csdn.net/jaket5219999/article/details/78465251
https://blog.csdn.net/linzi1994/article/details/83021070
2019.4.3补充
后来按照这个依然打不开，原因是缺少_gi这个库，所以把这个库拷到安装目录，如：
sudo cp -r /usr/lib/python3/dist-packages/gi/ /usr/local/python3/lib/python3.6/site-packages/后面的路径是python3.6的安装目录
参考：https://blog.csdn.net/Fei20140908/article/details/88168690
至于python安装，参考https://www.cnblogs.com/kimyeee/p/7250560.html
2、写的关于ORB提取的程序，但是报错如下
OpenCV Error: Assertion failed (0 <= roi.x && 0 <= roi.width && roi.x + roi.width
<= m.cols && 0 <= roi.y && 0 <= roi.height && roi.y + roi.height <= m.rows) in Mat,
file /tmp/binarydeb/ros-kinetic-opencv3-3.3.1/modules/core/src/matrix.cpp, line 538
terminate called after throwing an instance of 'cv::Exception'
what(): /tmp/binarydeb/ros-kinetic-opencv3-
3.3.1/modules/core/src/matrix.cpp:538: error: (-215) 0 <= roi.x && 0 <= roi.width
&& roi.x + roi.width <= m.cols && 0 <= roi.y && 0 <= roi.height && roi.y +
roi.height <= m.rows in function Mat
后经测试发现，是ORB初始化出问题
Ptr
但是这句是照着书写的，把书上的源码贴过来，可以解决上述问题，但是书上的这句和我自己写的这句是一样的啊，shit.
3、算不上BUG，使用快速最近邻算法FLANN去进行特征点匹配，结果用的时间比暴力匹配还多。
The number of ORB keypoints: 500
暴力匹配时间:0.00245851
FLANN加速匹配时间:0.0504945
其实貌似是一样的，FLANN最基础的也是寻找最近邻匹配
4、从网上下载的图片测试集，格式是PPM，在windows上打不开，最后竟然用qq影音打开了，意外之喜。这不是广告。
5、pip3 install 错误
Traceback (most recent call last):
File "/usr/bin/pip3", line 9, in
from pip import main
ImportError: cannot import name 'main'
解决：编辑 /usr/bin/pip 文件，修改代码
from pip._internal import main
6、2019.4.3
我屮艸芔茻，今天真的是炸了，装了下python3.6,结果把系统搞得乱七八糟，gedit无法使用，软件更新打不开，终端快捷键打不开，按ctrl浏览器疯狂新建页面，各种python的module找不到，头都大了，最后还是把新安的删除，再链接成自带的3.5的python,一切恢复如初，神奇
sudo ln -s /usr/bin/python3.5 /usr/bin/python
python3 默认安装在/usr/local/lib/python3.x中
7、2019.5.6
前两天不知怎么的roscors无法使用错误是
ImportError: No module named rosmaster.master_api
看到有个https://answers.ros.org/question/316120/importerror-no-module-named-rosmastermaster_api/提到这个问题，结果题主说重装一遍，头大，试着解决，改变python、pip版本，最后对ros初始化了下就好了
rosdep update