A high performance drop-in replacement for ev3dev-lang-python_. It does not support all features (eg. onboard buttons and screen), but it can be loaded concurrently with the ev3dev-lang-python. Use ev3fast for your performance critical loops, and ev3dev-lang-python for everything else. As an added bonus, your Python program will load significantly faster if you use only ev3dev-lang-python-fast, and do not import ev3dev-lang-python.
If you are not familiar with ev3dev-lang-python, you should start there first.
Read the documents for ev3dev-lang-python. Whatever applies there, applies here.
Download ev3fast.py from this repository, and put it in the same directory as your python program. You can alternatively put it in one of the directories along your python import path, but this is not recommended.
Sensor Benchmark (Loops per second)
===================== ====== ======= ============ Sensor Type ev3dev ev3fast Improvements ===================== ====== ======= ============ Touch 379 1886 5x Color (Ambient) 179 2343 13x Color (Color) 157 2375 15x Color (Raw RGB) 118 1859 16x Color (Reflected) 178 2021 11x Ultrasonic (Distance) 48 1882 40x Ultrasonic (Listen) 60 2094 35x Gyro (Angle) 45 2314 51x Gyro (Rate) 231 2174 9x Gyro (Rate & Angle) 152 2130 14x ===================== ====== ======= ============
Line Follower Benchmark
============================= ================ Program Type Loops per second ============================= ================ EV3-G 427 Python on ev3dev 32 Python on ev3dev with ev3fast 205 ============================= ================
The benchmark program is provided here if you want to try it out yourself.
.. code-block:: python
from time import perf_counter from ev3dev.ev3 import *
lMotor = LargeMotor('outA') rMotor = LargeMotor('outD') lSensor = ColorSensor('in1') rSensor = ColorSensor('in4')
LOOPS = 1000
startTime = perf_counter() for a in range(0,LOOPS): valueL = lSensor.raw valueR = rSensor.raw totalL = (valueL[0] + valueL[1] + valueL[2]) totalR = (valueR[0] + valueR[1] + valueR[2]) error = totalL - totalR lMotor.speed_sp = 200 + error rMotor.speed_sp = 200 - error lMotor.run_forever() rMotor.run_forever() endTime = perf_counter()
lMotor.stop() rMotor.stop()
print(str(LOOPS / (endTime - startTime)))
To benchmark the ev3fast version, uncomment the line..
.. code-block:: python
| class Sensor (address=None) | class TouchSensor (address=None) | class ColorSensor (address=None) | class UltrasonicSensor (address=None) | class GyroSensor (address=None) | class Motor (address=None) | class LargeMotor (address=None) | class MediumMotor (address=None)
These are replacements for ev3dev-lang-python, and all properties and
methods documented in the ev3dev-lang-python Read the Docs page_ are
supported. If address isn’t specified, the first device matching the class
will be loaded.
Add the following to the top of your file:
.. code-block:: python
import ev3fast
If you're loading ev3dev-lang-python concurrently, you can either import them under their own name...
.. code-block:: python
import ev3dev.ev3 as ev3 import ev3fast
slow = ev3.LargeMotor('outA') fast = ev3fast.LargeMotor('outB')
...or override ev3dev-lang-python...
.. code-block:: python
import ev3dev.ev3 as ev3 import ev3fast as ev3
fast = ev3.LargeMotor('outA')
Library Documentation
Class documentation for this library can be found on the
ev3dev-lang-python Read the Docs page_ . If it's a supported class
in ev3dev-lang-python-fast, it should (...probably) work identically to
ev3dev-lang-python.
.. _ev3dev: http://ev3dev.org .. _ev3dev-lang-python: https://github.com/ev3dev/ev3dev-lang-python .. _ev3dev-lang-python Read the Docs page: http://python-ev3dev.readthedocs.org/en/stable/