RAM PARABOLIC EQUATION

This source code is a translation in optimized C of the original ram code from Dr. David C. Calvo. See readme.orig for original instructions.

The original code shipped five sources:

• ram1.5.f
• ramclr.f
• rams0.5.f
• ramsurf1.5.f
• ramsurfclr2.0.f

The aim of this project is to make these program run faster by using several optimization techniques, while keeping the original behavior. This implies a move to the C language.

Download

Download the latest release with the following link: ramsurf-1.0.tar.gz

Building

Simply run:

./configure
make

You can install all the ramsurf variant as well as the headers using:

sudo make install

To turn on the vectorized C code, run:

make CFLAGS="-O2 -march=native"

All the traditional autotool flags work, including not building in the sources.

Testing

Compare the output produced by the FORTRAN code and the C code using:

make check

Using the Ramsurf Program

The C version mimics the FORTRAN interface and assumes all inputs are described in ram.in. It outputs two files: lt.line as plain text and tl.grid using the binary format used by FORTRAN.

The input format is the same as the one described in readme.orig:

# sample config. The first line is a header and is skipped.
freq zs zr          #frequency in Hz, source depth, receiver depth (data at this depth goes into tl.line)
rmax dr ndr         #maximum range (rmax), range step (delta r or dr), ndr (writes output every ndr range steps)
zmax dz ndz zmplt   #maximum depth of the whole computational domain (zmax), depth step (dz), ndz (output data at every ndz vertical point at a given range), vertical extent of the domain to output in tl.grid (zmplt).
c0 np ns rs         # reference sound speed, number of Pade terms (np), # of stability constraints (ns), radius of stability constraint (rs)
surface_range0 surface_depth0 # surface modeling
...
surface_rangeN surface_depthN
-1 -1               # END of SECTION marker
bathymetry_range0 bathymetry_depth0 #bathymetry modeling
...
bathymetry_rangeM bathymetry_depthM
-1 -1
ssp_depth0 ssp_value0       # sound speed profile in water
...
-1 -1
bssp_depth0 bssp_value0    # sound speed profile in bottom
...
-1 -1
bd_depth0 bd_value0    # density of bottom
...
-1 -1
ba_depth0 ba_value0    # attenuation of bottom
...
-1 -1
optional_range # if given, starts a new ssp description starting from this range, otherwise the previous values are valid for all remaining ranges
[...]

Using the Ramsurf Library

The C version can be used as a C library. Link with -lramsurflib and include ramsurf.h. The interface documentation is contained in the header file.