德雷克构建问题和 "from pydrake.all import"

Question

从源代码构建 drake 后，我在使用 from pydrake.all import (MathematicalProgram, Polynomial) 时遇到问题（参考 https://drake.mit.edu/python_bindings.html）。根据之前的 link，安装步骤为：

git clone https://github.com/RobotLocomotion/drake.git
mkdir drake-build
cd drake-build
cmake ../drake -DWITH_MOSEK=ON
make -j
cd drake-build
export PYTHONPATH=${PWD}/install/lib/python3.6/site-packages:${PYTHONPATH}

安装后运行 from pydrake.all import (MathematicalProgram, Polynomial) 我收到以下错误：

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "$HOME/drake-build/install/lib/python3.6/site-packages/pydrake/all.py", line 34, in <module>
    from .perception import *
ImportError: ImportError: $HOME/drake-build/install/lib/python3.6/site-packages/pydrake/systems/framework.so: undefined symbol: _ZNK5drake7systems6SystemIdE19DoCheckValidContextERKNS0_11ContextBaseE

如果我使用夜间构建二进制文件（而不是从源代码构建），我不会收到此错误，但我在夜间构建二进制文件时遇到了不同的问题，我想依赖从 git.

使用 Ubuntu 18.04，Python3.6.

Answer 1

您是否尝试过设置 PYTHONPATH 环境变量？你可以做

cd drake-build
export PYTHONPATH=${PWD}/install/lib/python3.6/site-packages:${PYTHONPATH}

如https://drake.mit.edu/python_bindings.html#building-the-python-bindings

所述

Answer 2

通过删除构建目录并重复 https://drake.mit.edu/python_bindings.html#building-the-python-bindings 中给出的步骤解决：

rm -rf drake-build
mkdir drake-build
cd drake-build
cmake ../drake -DWITH_MOSEK=ON
make -j
cd drake-build
export PYTHONPATH=${PWD}/install/lib/python3.6/site-packages:${PYTHONPATH}

之前的构建一定是不稳定的，并且这些痕迹阻碍了之后的正确构建。我不确定第一个“错误构建”的根本原因，但它似乎与我之前的提交 (4bd63e3ee) 无关，因为从该提交重新构建也工作正常。

德雷克构建问题和 "from pydrake.all import"

Problems with drake build and "from pydrake.all import"

drake