1. Add Solver::Options::use_mixed_precision_solves,
and Solver::Options::max_num_refinement_iterations.
2. Make SparseCholesky::Create return a unique_ptr.
3. SparseCholesky::Create now takes LinearSolver::Options
as an argument.
4. IterativeRefiner's constructor does not require num_cols
as an argument.
5. SparseNormalCholeskySolver now uses a separate rhs vector.
This basic implementation results in a 10% reduction in solver time
and 30% reduction in linear solver memory usage.
Change-Id: I6830f32cae2febf082d2733262eb2c9f0482b0ea
This adds a callback mechanism to for users to get notified just
before jacobian and residual evaluations. This will enable
aggressive caching and sharing of compute between cost functions.
Change-Id: I67993726920218edf71ab9ae70c34c204756c71a
1. Solver::Options::num_threads now controls parallelism in Ceres
Solver. The user specified value of
Solver::Options::num_linear_solver_threads is ignored.
2. If the user specifies Solver::Options::num_linear_solver_threads
and it is different from Solver::Options::num_threads,
a warning is printed.
3. Solver::Summary:num_linear_solver_threads_given and
Solver::Summary::num_linear_solver_threads_used are also
deprecated and are always set to Solver::Summary::num_threads_given
and Solver::Summary::num_threads_used.
Change-Id: I20b9336d9336e400e6f0a15b63857c0c43eb271c
A Ceres Context holds common global state that can be re-used within
Ceres. The Context current contains a thread pool if compiling with
C++11 threading support. Threads are expensive to create and destroy so
it is good to maintain across multiple Ceres solves.
Tested by compiling with and without TBB support and ran unit tests. Ran
bazel as well.
Change-Id: I82f598dfae642aa0e81a6039dc174608a5e8dbfb
There was a bug in the trust region preprocessor where no fill
reducing ordering was computed for the case of SPARSE_SCHUR + CX_SPARSE
but this was not signaled to SchurComplementSolver, so it was using
a naive/natural ordering. To fix this two changes are made:
1. TrustRegionProcessor's logic for signaling the ordering to the
linear solver has been re-worked. The surrounding code has also
been re-organized for better readability.
2. In SchurComplementSolver::SolveReducedSystem the row and column
block structure has been added to the CompressedRowSparseMatrix
containing the Schur complement so that block AMD can be used.
As a result of these changes the linear solve time for
problem-744-543562-pre.txt has been brought down from 58 seconds to
35 seconds.
Change-Id: I4d82efce05175260f97b1f925f8a1b4a9d650cae
Since Ceres is moving to using GitHub for issues, and the Google
Code URL in the current copyright header will soon become invalid,
update all the headers.
Change-Id: I1fce70375d1bcf098591f07b4d8f01a5c1e0789c
For historical reasons we had a "using namespace std;" in port.h. This
is generally a bad idea. So removing it and along the way doing a bunch
of cpplint cleanup.
Change-Id: Ia125601a55ae62695e247fb0250df4c6f86c46c6
Up till now ITERATIVE_SCHUR evaluates matrix-vector products
between the Schur complement and a vector implicitly by exploiting
the algebraic expression for the Schur complement.
This cost of this evaluation scales with the number of non-zeros
in the Jacobian.
For small to medium sized problems there is a sweet spot where
computing the Schur complement is cheap enough that it is much
more efficient to explicitly compute it and use it for evaluating
the matrix-vector products.
This changes implements support for an explicit Schur complement
in ITERATIVE_SCHUR in combination with the SCHUR_JACOBI preconditioner.
API wise a new bool Solver::Options::use_explicit_schur_complement
has been added.
The implementation extends the SparseSchurComplementSolver to use
Conjugate Gradients.
Example speedup:
use_explicit_schur_complement = false
Time (in seconds):
Preprocessor 0.585
Residual evaluation 0.319
Jacobian evaluation 1.590
Linear solver 25.685
Minimizer 27.990
Postprocessor 0.010
Total 28.585
use_explicit_schur_complement = true
Time (in seconds):
Preprocessor 0.638
Residual evaluation 0.318
Jacobian evaluation 1.507
Linear solver 5.930
Minimizer 8.144
Postprocessor 0.010
Total 8.791
Which indicates an end-to-end speedup of more than 3x, with the linear
solver being sped up by > 4x.
The idea to explore this optimization was inspired by the recent paper:
Mining structure fragments for smart bundle adjustment
L. Carlone, P. Alcantarilla, H. Chiu, K. Zsolt, F. Dellaert
British Machine Vision Conference, 2014
which uses a more complicated algorithm to compute parts of the
Schur complement to speed up the matrix-vector product.
Change-Id: I95324af0ab351faa1600f5204039a1d2a64ae61d
TrustRegionPreprocessor was not setting Minimizer::Options::is_constrained.
This meant that the line search for bounds constraints was not being
invoked for bounds constrained problems.
And some minor lint cleanup.
Change-Id: I18852cfaf1b33fd90b7d8c196f2063c128126658
1. Base class for preprocessors.
2. A preprocessor for problems that will be solved using
the trust region minimizer.
3. Added sanity tests to the program reordering options
for Schur type linear solvers.
4. Tests for the TrustRegionPreprocessor.
Change-Id: I88cd926f0053bbbf2bd6b11e03ec55b8bf473cf1
Sameer Agarwal