tree 1332e56205388ce1f8baa97a7c46192331415157
parent a614f788a34ea86dd9f679b779ffbf920db45aa6
author Sameer Agarwal <sameeragarwal@google.com> 1590433923 -0700
committer Sameer Agarwal <sameeragarwal@google.com> 1590643541 +0000

Update the section on Preconditioners

Re-organize the section, add some more references and details for
existing preconditioners and add documentation for the SUBSET
precondition.

https://github.com/ceres-solver/ceres-solver/issues/490

Change-Id: I93d0af819c160f5e4ce48b18202f629ddb92ca7b