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
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.
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%.
- 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.
Passing an unsigned value to abs() causes compilation error in gcc 6.1.1
(and doing that doesn't make sense too).
As a bonus, this patch fixes the code, since, for two unsigned integers
a and b, such that a > b, (a - b) without the casting to a signed
integer would produce garbage in the context of this patch. The type
int32_t is enough for the cases covered by this patch.
We actually don't want a flexible array in this union, but rather a way
to access it byte by byte. This fixes the build for gcc >= 6
In file included from ../../libraries/AP_GPS/AP_GPS_UBLOX.cpp:23:0:
../../libraries/AP_GPS/AP_GPS_UBLOX.h:387:23: error: flexible array member in union
uint8_t bytes[];
^
compilation terminated due to -Wfatal-errors.
In file included from ../../libraries/AP_Mount/AP_Mount.cpp:9:0:
../../libraries/AP_Mount/AP_Mount_Alexmos.h:291:23: error: flexible array member in union
uint8_t bytes[];
^
compilation terminated due to -Wfatal-errors.
We actually don't want a flexible array in this union, but rather a way
to access it byte by byte. This fixes the build for gcc >= 6
In file included from ../../libraries/AP_GPS/AP_GPS.cpp:24:0:
../../libraries/AP_GPS/AP_GPS_ERB.h:93:23: error: flexible array member in union
uint8_t bytes[];
^
compilation terminated due to -Wfatal-errors.
In file included from ../../libraries/AP_GPS/AP_GPS_ERB.cpp:22:0:
../../libraries/AP_GPS/AP_GPS_ERB.h:93:23: error: flexible array member in union
uint8_t bytes[];
^
compilation terminated due to -Wfatal-errors.
In file included from ../../libraries/AP_GPS/AP_GPS_MTK.cpp:25:0:
../../libraries/AP_GPS/AP_GPS_MTK.h:75:23: error: flexible array member in union
uint8_t bytes[];
^
compilation terminated due to -Wfatal-errors.
In file included from ../../libraries/AP_GPS/AP_GPS_MTK19.cpp:26:0:
../../libraries/AP_GPS/AP_GPS_MTK.h:75:23: error: flexible array member in union
uint8_t bytes[];
^
compilation terminated due to -Wfatal-errors.
In file included from ../../libraries/AP_GPS/AP_GPS_SIRF.cpp:22:0:
../../libraries/AP_GPS/AP_GPS_SIRF.h:101:23: error: flexible array member in union
uint8_t bytes[];
^
compilation terminated due to -Wfatal-errors.
In file included from ../../libraries/AP_GPS/AP_GPS_UBLOX.cpp:23:0:
../../libraries/AP_GPS/AP_GPS_UBLOX.h:387:23: error: flexible array member in union
uint8_t bytes[];
^
compilation terminated due to -Wfatal-errors.
Instead of a couple seconds, make it about 15sec. This makes TECS happy by not glitching the height demand as much. When applied too fast the TECS height demand causes a large single oscillation as it chases the filter lag.
Gustavo Jose de Sousa
dgrat
Tom Pittenger
Lucas De Marchi
Peter Barker
Andrew Tridgell
Rustom Jehangir
Jonathan Challinger
Ricardo de Almeida Gonzaga