Expression functions

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Knut Morten Okstad edited this page Jun 4, 2019 · 3 revisions

Expression functions

IFEM allows for specification of boundary conditions, analytic solutions and numerous other properties as symbolic expressions. This page is an overview of the available symbols.

Available variables

x - The x-coordinate in evaluation point
y - The y-coordinate in evaluation point
z - The z-coordinate in evaluation point
t - The physical time t

Available mathematical functions

sqrt(x)
sin(x), cos(x), tan(x)
asin(x), acos(x), atan(x), atan2(y,x)
sinh(x), cosh(x), tanh(x)
log(x)
ln(x)
exp(x)
logn(x,n)
ceil(x)
floor(x)
deg(x) - convert from radians to degrees
rad(x) - convert from degrees to radians
pow(x,n)

Available commonly used constants

PI - The value of π
E - The base e of the natural logarithm

Available logical constructs

if(condition,iftrue,iffalse)
clip(value,lowbound,upperbound)
clamp(value,lowerclamp,upperclamp)

These can be used in combination with

The available conditions

and(x,y)
or(x,y)
not(x)
equal(x,y) - (x=y)
above(x,y) - (x > y)
below(x,y) - (x < y)

Vector functions

For vectorial functions, separate the components using a '|' character