PyRAM

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Python adaptation of the Range-dependent Acoustic Model (RAM).

RAM was created by Michael D Collins at the US Naval Research Laboratory. This adaptation is of RAM v1.5, available from the Ocean Acoustics Library at https://oalib-acoustics.org/models-and-software/parabolic-equation

The purpose of PyRAM is to provide a version of RAM which can be used within a Python interpreter environment (e.g. Spyder or the Jupyter notebook) and is easier to understand, extend and integrate into other applications than the Fortran version. It is written in pure Python and achieves speeds comparable to native code by using the Numba library for JIT compilation.

The PyRAM class contains methods which largely correspond to the original Fortran subroutines and functions (including retaining the same names). The variable names are also mostly the same. However some of the original code, e.g. subroutine zread, is unnecessary when the same purpose can be achieved using widely available Python library functions, e.g. from NumPy or SciPy, and has therefore been replaced.

A difference in functionality is that sound speed profile updates with range are decoupled from seabed parameter updates, which provides more flexibility in specifying the environment, e.g. if the data comes from different sources.

PyRAM also provides various conveniences, e.g. automatic calculation of range and depth steps, though these can be overridden using keyword arguments.