Moonlight

Matplotlib wave plotting and animation made easy

Installation

• For pip release - pip install moonlight
• For source build -

git clone https://github.com/CharlesAverill/moonlight.git moonlight
cd moonlight
python setup.py install

Usage

from moonlight import waves, utils

# Create a damped Sine wave with amplitude, period 2
sine = waves.Sine(amplitude=2, period=2,
                    decay_constant=.25)

# Set range of plot
utils.x_range(-3, 3)
utils.y_range(-4, 4)

# Move axes to center
utils.center_axes()

# Plot 2 periods of the wave (static)
sine.plot(2)

Animation

Waves can also be animated! Just replace <wave_object>.plot() with <wave_object>.animate()!

animate parameters

• speed - The speed at which the animation will play. Some waves have their default speed adjusted so that animation can be seen easily.
  • When combining a Square or Sawtooth wave with a Sine or Cosine wave, the sum of the functions naturally grows at an incredibly slow rate, so speed should be set to a multiple of 10**14 to be able to view animations properly.
• line_width - Sets line width
• framerate - Measured in ms, this is the time gap between two frames being displayed. Default is 17ms or ~60fps.

Supported Waves

• Sine
• Cosine
• Square
• Sawtooth
• Wave - This is a parent class for the previous waves. Custom waves can be implemented by inheriting this class.

Wave parameters

• amplitude: float = 1 - Initial wave amplitude
• period: float = <varies by wave> - Period of wave
• offsets: Tuple(float [x], float [y]) = (0, 0) - X- and Y- offsets of the wave
• decay_constant: float = 0 - If nonzero, function will decay according to e^(-<decay>x)wavefunc(x). Trig functions only.
• resolution: int = 500 - Number of x-values that will be generated upon graphing.

Wave operators

Waves can be operated on by each other and by scalar values.

from moonlight.waves import Sine

s1 = Sine()
s2 = Sine(amplitude=2)

add_waves = s1 + s2 # sin(x) + 2sin(x) = 3sin(x)
add_scalar = s1 + 3 # sin(x) + 3

sub_waves = s1 - s2 # sin(x) - 2sin(x) = -sin(x)
sub_scalar = s1 - 3 # sin(x) - 3

mul_waves = s1 * s2 # sin(x) * 2sin(x) = 2sin(x)^2
mul_scalar = s1 * 3 # sin(x) * 3 = 3sin(x)

div_waves = s1 / s2 # sin(x) / 2sin(x) = 1/2
div_scalar = s1 / 3 # sin(x) / 3 = (1/3)sin(x)

call_waves = s1(s2) # sin(2sin(x))
call_scalar = s1(3) # sin(3) ≈ .14112