The issue was caused by the fact that in this version
of MSVC unordered_map class is defined in <unordered_map>
header file, but this file declares the class int std::tr1
namespace.
This confused existing assumption that if there's an
existing <unordered_map> file then class is declared
in std namespace.
Added an extra check to CMake which detects whether
it's std or std::tr1 which actually contains class
of unordered_map.
This might be changed/cleaned in the future, for
now committing to our repository to solve compilation
error on windows.
Details of the patch in upstream can be found there:
https://ceres-solver-review.googlesource.com/#/c/4371/
- A richer Problem API.
- DynamicNumericDiffCostFunction.
- Faster ITERATIVE_SCHUR solver.
- Faster SCHUR_JACOBI preconditioner.
- Faster Jacobian evaluation.
- Faster visibility based preconditioning using single linkage clustering.
Also re-wrote rules for unordered collections detection,
should work on all platforms and compilers now :)
For Blender this release is interesting because of:
- Covariance estimation (not used in Blender yet, but now we
might use it for keyframe selection instead of havingown
implementation).
- Significant performance improvements to loss function and
dense linear solvers and automatic differentiation.
Unfortunately, didn't notice speedup of tracking itself,
but camera reconstruction now happens around 2 times faster
on my laptop,
- Better inner iteration step acceptance and stopping.
This brings a fixes for threading issue in BLAS
making BA step more robust (there were some in-detemrinacy
caused by this threading issue).
Also brings some optimizations, which does not directly
affect on blender.
Thins brings up some speed improvements:
SPARSE_SCHUR is approx 1.3-1.5x times faster
ITERATIVE_SCHUR is approx 1.2x times faster
For blender this means camera solution go a bit
faster now. Would not have affect on tracking
speed.
Also made it theraded linear solver, seems it makes
sense for iterative schur with inner iterations
enabled.
Use OpenMO's max therads called from bundler code
to detect how many threads to use. Could be changed
in a way that number of threads is passing in options
from blender side in the future.
Also removed redundant V3D definition from compiler's
flags.
This is helpful because it brings CHOLMOB-free ITERATIVE_SCHUR and
SCHUR_JACOBI which is really nice for new upcoming bundle adjustment.
If also includes all the local fixes we made locally.
There're lots of other improvements/fixed which are not currently
would be so much visible in Blender, but which opens doors for some
great improvements in future.
This should contain real fixes for Windows, making it more robost and hopefully
faster (due to proper collection port) on that platform.
Also hack to fix Eigen alignment shouldn't be needed anymore.
Also on platforms which have got broken TR1 collections it's better to define
CERES_NO_TR1 instead of using Boost hacks. Made changes to Scons and CMake,
but can not check if this indeed works since i don't have OSX here.
As far as i remember Keir, this should be safe for our usages of ceres
and it should save noticeable amount of time and used memory when
compiling blender with libmv support.
Quick tests with tracking went smooth after this.
Currently only put sources of Ceres library into extern/libmv/third_party and
setup CMake and SCons building systems.
Integration details:
- Even CMake build files are not re-used from Ceres's trunk: they're using some
automatic stuff detection like glog, pthreads, protobuf and so and it's not
so clear how to re-use that files without modifications.
And IMO it's easier if build files are getting re-generated automatically to
match Blender-specific setup rather than keeping changes made locally in
Blender in sync when re-bundling Ceres library. Especially in case when it's
already needed to support SCons build system.
- Integrated only actual sources, all tests were stripped. Probably it'll be nice
to have them, but they'll need clear integration with current module test stuff
in Blender.
- Suitesparse was disabled. It'll help a lot having it, but there are some difficulties
making cholmod working fine on windows. Would be added in future
- collections_port.cc was also stripped. It's not used by Ceres's upstream and
it gives compilation error (undefined uint32 -- looks like namespace issue).
- Currently all schur eliminators are included. Not sure if it makes sense,
also not sure if it makes sense having them switchable on and off -- IMO better
to have single configuration which works and does not require special tweaks
after everything was set up.
To bundle updated version of Ceres:
- Go to extern/libmv/third_party/ceres folder
- Run ./bundle.sh
This will checkout fresh Ceres snapshot of Windows branch (which is currently
most interesting from integration into Blender POV), apply all patches listed
in patches/series and copy needed files into Blender's working copy. This will
also re-generate CMake/SCons build rules.
If you'll need extra files from Ceres repository which are not present in
Blender, you'll need to copy them manually and then run ./mkfiles.sh from
extern/libmv/third_party/ceres folder which will update list of files used
by Blender.
Thanks to Leir Mierle and Sameer Agarwal (and all others who helped developing
Ceres) this library and thanks to Keir Mierle with help integrating it into Blender!
