tree 110b54e2eb31d0bf620ae712977187733bdfb54c
parent 4ffec20a4400197c015fe7bbdb3a3836265d46a0
author Sameer Agarwal <sameeragarwal@google.com> 1504076799 -0700
committer Sameer Agarwal <sameeragarwal@google.com> 1506361455 +0000

Delete cost and loss functions when not in use.

Delete CostFunctions and LossFunctions when there are no more
ResidualBlocks referring to them. This is done by maintaining
a map with reference counts for CostFunctions and
LossFunctions.

The same maps are also used at the time of the destruction
of the ProblemImpl object itself. Previously vectors of these
objects were constructed, uniqed and the objects destroyed.

The update to the maps increases the cost of calling AddResidualBlock,
this has been mitigated, actually making AddResidualBlock faster, by
reusing a temporary vector rather than allocating one on the stack
every time.

Change-Id: I28b5287511713d28069ae428e2ff69224c0d03b4