Simulation Setup

Directory Layout

All simulations run from the bin/ directory. You need to place there:

• input.txt — main configuration file
• The mesh file (.msh from Gmsh, or generated from Cartesian parameters)
• m_user_data.f90 — Fortran file defining bathymetry and initial conditions (recompiled at each run)
• Any required external forcing or boundary files (see External Input Files)

Setting Up input.txt

All parameters have sensible defaults. A minimal input.txt for a Gmsh mesh:

mesh_name   = mymesh.msh
simu_time   = 12 hours
cfl         = 0.5
w_tecplot   = 10000
dt_tecplot  = 10 minutes

A Cartesian mesh (no Gmsh file):

nx          = 200
ny          = 100
lx          = 100000.
ly          = 50000.
bc_N        = wall
bc_S        = wall
bc_W        = neumann
bc_E        = wall
simu_time   = 6 hours

See the complete parameter reference for all available parameters, and Boundary Conditions for the full BC type catalogue.

Setting Up m_user_data.f90

m_user_data.f90 defines the problem geometry and initial conditions. It is a Fortran submodule of m_Tolosa_sw and is recompiled at every run (make mrun). It must implement:

Procedure	Role
user_parameters(dof, input, mesh)	called once before all initializations; read custom parameters, precompute data, open files
bathy_user(x, y)	return bathymetry (positive upward) at point (x, y)
h0_user(x, y, b)	return initial water depth at (x, y) given bathymetry b
u0_user(x, y)	return initial x-velocity at (x, y)
v0_user(x, y)	return initial y-velocity at (x, y)
bc_user(tag)	return boundary value for a given named tag

user_parameters — the Setup Hook

Called after the mesh is loaded and input.txt parsed, but before bathymetry, BCs, initial state, friction, forcings, and numerical schemes are initialized. Use it to:

• Declare custom input.txt parameters via input%add_get:

  call input%add_get( 'h_0'     , default='1.d3' , kind=rtype , value=h_0     )
  call input%add_get( 'n_bathy' , default='1000' , kind=itype , value=n_bathy )

• Precompute geometry using globals: lx, ly, mesh%nc, proc/np, g, pi, pathto()
• Read/write auxiliary binary files:

  open( unit=new_unit(unit), file=pathto('bathy.bin'), form='unformatted', ... )

• Generate randomised fields using genrand(min, max) (from Tolosa-lib)

Data Path

All file names in input.txt are resolved through pathto(), which prepends data_path (default "./") to any relative path.

Override at runtime:

./Tolosa_sw -data-path /path/to/data

Absolute paths are passed through unchanged.