Update SobolEngine docstring w/ correct behavior (#62548)
Summary:
Sobol was modfied to not drop the first point. This update reflects this behavior in the docstring.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/62548
Reviewed By: qingfeng10
Differential Revision: D30035627
Pulled By: Balandat
fbshipit-source-id: 64c659ea30c0c929778da3b58041875834e25e9a
