tree 1baa105e26c9642cba5a5d080af489e72f04e7cc
parent 1f17f56c4efc3f2175b7f1c45c982809bb4b9fe4
author Sameer Agarwal <sameeragarwal@google.com> 1371131878 -0700
committer Sameer Agarwal <sameeragarwal@google.com> 1371131878 -0700

Fix a reallocation bug in CreateJacobianBlockSparsityTranspose.

CreateJacobianBlockSparsityTranspose starts with a conservative
estimate of the size of the block sparsity pattern of the Jacobian.
When the Jacobian has more non-zeros than that, the TripletSparseMatrix
being used to store the sparsity has a Reallocate method which
allows one to resize the matrix and IF num_nonzeros is set, then the
existing values in the array are also copied into the newly allocated
memory.

Unfortunately the pattern we follow in ceres code is to call
set_num_nonzeros after one is done populating the sparsity pattern
of a matrix. This does not mix well with Reallocate and results
in the matrix having uninitialized memory.

This patch fixes this problem and adds a test that verifies the fix.

Thanks to Yuliy Schwartzburg for reporting this bug and providing
code to reproduce it.

Change-Id: I58583714ffaebd880d85af16e3685b2d6ee053e8