Commit Graph

14 Commits

Author SHA1 Message Date
Lucas De Marchi fa6f2c6b67 AP_Math: fix some coding style mistakes
- fix alignement of &
    - remove const from bool arguments
2016-05-16 19:08:36 -03:00
Gustavo Jose de Sousa 9d34b3b996 AP_Math: AP_GeodesicGrid: make all methods static
Since all members are.
2016-05-16 19:08:36 -03:00
Gustavo Jose de Sousa 77223a7fcb AP_Math: AP_GeodesicGrid: make data static
That gives the change of storing that data in flash storage in some
architectures. That doesn't happen yet though, some extra changes are required
for that to happen.
2016-05-16 19:08:36 -03:00
Gustavo Jose de Sousa fd2428db34 AP_Math: AP_GeodesicGrid: reduce number of _neighbor_umbrellas items
Only the first half is necessary. The values for the other half can be derived.
2016-05-16 19:08:36 -03:00
Gustavo Jose de Sousa 43d9e00ab7 AP_Math: AP_GeodesicGrid: use uint8_t for _neighbor_umbrellas
All integers there are limited to the range [0,20), so uint8_t is enough.
2016-05-16 19:08:36 -03:00
Gustavo Jose de Sousa 54889e4175 AP_Math: AP_GeodesicGrid: reduce number of inverses by half
We don't actually need all of them, since the second half is for the opposite
triangles. In that case we just need to negate the resulting vector when
changing basis.
2016-05-16 19:08:36 -03:00
Gustavo Jose de Sousa f31161ecb6 AP_Math: AP_GeodesicGrid: remove triangles
There's no need to keep those triangles, since we just need the inverses.
2016-05-16 19:08:36 -03:00
Gustavo Jose de Sousa 8e8ab3af96 AP_Math: AP_GeodesicGrid: remove section_triangle() function
That function was only being used by the unit tests and the benchmark. In order
to remove memory usage, the triangles will be removed, since we don't actually
need to keep them in real situations. Thus, this patch removes that function
and copy those triangles to the test and benchmark.
2016-05-16 19:08:36 -03:00
Gustavo Jose de Sousa c7eb46fae2 AP_Math: AP_GeodesicGrid: optimize _from_neighbor_umbrella()
This is the second optimization. With that we don't have to iterate over the
umbrella's components.

The table below summarizes the mean CPU time in ns from the brenchmark results
on an Intel(R) Core(TM) i7-3520M CPU @ 2.90GHz processor:

       | Naive implementation | First Optimization | Second Optimization
------------------------------------------------------------------------
Min.   |                 26.0 |              28.00 |                26.0
1st Qu.|                 78.0 |              48.75 |                39.0
Median |                132.0 |              57.00 |                41.0
Mean   |                130.1 |              61.20 |                41.6
3rd Qu.|                182.2 |              76.00 |                47.0
Max.   |                234.0 |              98.00 |                54.0
2016-05-16 19:08:36 -03:00
Gustavo Jose de Sousa eb90ef23a1 AP_Math: AP_GeodesicGrid: fix algorithm for null vector
If v is the null vector, then alpha * v is still the null vector for any alpha
as a real number. That means that the null vector doesn't cross any section.
2016-05-16 19:08:36 -03:00
Gustavo Jose de Sousa c28c3265c8 AP_Math: AP_GeodesicGrid: optimize with neighbor umbrellas
This is a first optimization of the algorithm. The struct for the neighbor
umbrella has only one member, but new members will be added in the next
optimization.

The table below summarizes the mean CPU time in ns from the brenchmark results
on an Intel(R) Core(TM) i7-3520M CPU @ 2.90GHz processor:

Cases  | Naive implementation | First Optimization
--------------------------------------------------
Min.   |                 26.0 |              28.00
1st Qu.|                 78.0 |              48.75
Median |                132.0 |              57.00
Mean   |                130.1 |              61.20
3rd Qu.|                182.2 |              76.00
Max.   |                234.0 |              98.00

This optimization reduces the mean time for the worst case (Max. line) by more
than 50%.
2016-05-16 19:08:36 -03:00
Gustavo Jose de Sousa 0ff05b7af3 AP_Math: test_geodesic_grid: test triangles indexes
That helps figuring out which intermediate step failed the high level call.
2016-05-16 19:08:36 -03:00
Gustavo Jose de Sousa 4398e1e49b AP_Math: AP_GeodesicGrid: change order of triangles
- Change the order of the icosahedron triangles so that there's a uniform way of
finding the opposite triangle. The order visually still makes sense.

 - Change test to accommodate the order change.
2016-05-16 19:08:36 -03:00
Gustavo Jose de Sousa b299261ad4 AP_Math: AP_GeodesicGrid: add first implementation
The search for the geodesic section is still naive in this version.
Additionally, add unit tests.
2016-05-16 19:08:35 -03:00