Porting from v0.3
The UnderwaterAcoustics.jl API was changed in v0.4 to make it more flexible to accommodate more types of acoustic propagation models, and for improved readability. The changes are summarized below to aid in porting old code to the new version.
Underwater acoustics
The following functions have been renamed:
| Old function name | New function name |
|---|---|
bubbleresonance |
bubble_resonance |
indBperλ |
in_dBperλ |
reflectioncoef |
reflection_coef |
surfaceloss |
surface_reflection_coef |
waterdensity |
water_density |
Environment description
Various attributes of the environment description are now directly accessed as fields, rather than through accessor methods:
| Old accessor | New field access |
|---|---|
altimetry(env) |
env.altimetry |
bathymetry(env) |
env.bathymetry |
ssp(env) |
env.soundspeed |
salinity(env) |
env.salinity |
waterdensity(env) |
env.density |
seasurface(env) |
env.surface |
seabed(env) |
env.seabed |
The environment description supports fields that can vary with spatial coordinates. This removes the need wrapping of constants with ConstantDepth(), IsoSSP(), etc. Instead, constant fields are just represented by the real numbers directly. Quantities varying with spatial coordinates are represented generically using a SampledField rather than specific types such as SampledSSP.
The defaults for an UnderwaterEnvironment have also changed to become more generic. For example, the default seabed is now a RigidBoundary and the default sea surface is a PressureReleaseBoundary. Contrast this against the arbitrary default in v0.3 of the default seabed being a SandySilt.
Noise is no longer defined as part of the environmental description, and is defined as part of the new channel modeling API.
Propagation modeling
The PekerisRayModel is now renamed to PekerisRayTracer, and takes in maximum number of bounces as an optional argument, instead of number of rays. The eigenrays function is no longer supported, but its functionality is provided by arrivals. While eigenrays was specific to ray models, arrivals is more generic and may return modes, etc, depending on the propagation model. A few other functions have been renamed:
| Old function | New function |
|---|---|
PekerisRayModel(env, nrays) |
PekerisRayTracer(env, maxbounces) |
eigenrays |
arrivals |
transmissionloss |
transmission_loss |
transfercoef |
acoustic_field |
impulseresponse |
impulse_response |
The plotting API no longer takes special keyword arguments such as sources and receivers. Instead, plot recipes are provided for each of the data types directly. So we can plot sources, receivers, arrivals, etc directly:
env = UnderwaterEnvironment(bathymetry=20, seabed=SandyClay)
pm = PekerisRayTracer(env)
tx = AcousticSource(0.0, -5.0, 1000.0)
rx = AcousticReceiver(100.0, -10.0)
rays = arrivals(pm, tx, rx)
plot(env)
plot!(tx)
plot!(rx)
plot!(rays)Acoustic simulations
The record and recorder functions used for acoustic simulations have been removed. Instead, a new channel modeling API with a transmit function provides similar functionality, but is a lot more flexible.
Example:
ch = channel(pm, tx, rx, 192000)
y = transmit(ch, x) # for some signal x
The channel API also supports channel replay and data-driven acoustic channels that are not derived from propagation models.
Specific sources such as Pinger and NarrowbandAcousticSource have been removed. Other packages such as SignalAnalysis may be used to create a diverse set of sampled signals that can be transmitted through the acoustic channel using the transmit function.