MPI-AMRVAC  3.1
The MPI - Adaptive Mesh Refinement - Versatile Advection Code
Variable names

Dimensions, Directions, and Limits

name description
ndim number of spatial dimensions (1, 2, 3)
^D expands to 1,..,ndim
^ND expands to the value of ndim
ndir number of vector components (1, 2, 3)
^LIM expands to min,max
^L expands to min1,min2,min3,max1,max2,max3
^S expands to min1:max1,min2:max2,min3:max3
^T expands to lo1:hi1,lo2:hi2,lo3:hi3

Differential Equations and Physical Quantities

name description
ps(igrid)%w w - conservative variables
pso(igrid)%w w at beginning of current time step
ps(igrid)%x x - spatial variables
global_time time
it integer counter of temporal iterations
qdt the time step to be used in a subroutine/function

Indices of variables in w array:

name description
rho_ density
e_ energy density
p_ pressure (primitive form of e_, same index)
mom(1:ndir) momentum density
mag(1:ndir) magnetic field

Coordinate system

name description
r_ R direction for polar or cylindrical symmetry
phi_ PHI direction for polar or cylindrical symmetry
z_ Z direction for polar or cylindrical symmetry

Constants

name description
dpi the value of pi (double precision)
smalldouble a small number above machine precision
bigdouble a very large number

General Tokens

name description
i* index for *
h* i*-1 Previous index
j* i*+1 Next index
n* number of *. Usually refers to an index i*=1..n*.
d* difference of *, derivative of *
grad* spatial derivative of *
l* limited value
*C add 1/2 to spatial index/indices
*CT add 1/2 to temporal index
*R on the right
*L on the left
*I input (eg. ixI^L are the limits of useful part of input)
*O output (eg. ixO^L are the limits of useful part of output)
*2 on the power two, squared
sqr* square root of
kr Kronecker delta 3*3 tensor
lvc Levi-Civita 3*3*3 tensor
q* local variables to avoid name conflict with common ones
usr* user defined subroutines and parameters
*_ indexname, integer parameters defined for legible code

Grid Related Tokens

name description
G grid (boundary ghost cells included)
M mesh (without boundary layers)
B boundary
nghostcells block boundary cells width in number of cells
volume volume of mesh
dvolume volume of cell
surface surface of cell edge
normal normalized normal vector of cell surface

I/O Related Tokens

name description
file input/output files
read reading from parameter or data files
save writing into output files
last last occasion (e.g. for saving into file)
*ini file containing initial conditions
*out file containing full results
head header string in files
unit units for open, close, read and write statements
unitterm standard output

Method Related Tokens

name description
type* types (e.g. boundary, flow variables)
par parameters
eq equation
fix fixing certain problems (e.g. divbfix)
error error quantification
err same as error
courant Courant condition
step step in multistep methods
advance advancing from time t to t+dt
advect advecting in directions idimmin..idimmax
advect1 a single step of a multistep time integration in advect

Subroutine Name Tokens

name description
get* subroutine names for getting values (e.g. get_flux)
add* subroutine names for adding values (e.g. add_source)

Examples

For example the variable name

ditsave = d + i + t + save

is the **d**ifference in the **i**ndices of the **t**imes between **save**s into the output files, i.e. the frequency of saving snap shots measured in time steps. Another example:

ixGhi^D = i + x + G + hi + ^D

is the highest possible indices for the coordinates for the grid for each dimensions.