<< Click to Display Table of Contents >> Navigation:  Sample Problems > Usage > Functions > function_definition

{  FUNCTION_DEFINITION.PDE  

  This example demonstrates the use of functional parameter definitions.

 

}

 

title 'Functional Parameter Definition test'

Variables

    u

 

definitions

 

{ Declare "Sq" a function of argument "A".

      "A" is a dummy name that represents the actual argument passed

       by an invocation.  }

 Sq(a) = a*a

{ Define two functions for use in domain layout.

       The "n" argument rotates by 90 degree increments.}

 xx(n) = cos(n*pi/2)        

 yy(n) = sin(n*pi/2)

 

equations

{ invoke the "Sq" function as a component of the equation.  This makes

   the system nonlinear }

 U: div(grad(u)) + 80*Sq(u)*dx(u) +4 = 0

 

boundaries

  region 1

      start(xx(0),yy(0))

      value(u)=0

      line to (xx(1),yy(1))   { definition evaluates corners of a diamond }

            to (xx(2),yy(2))

            to (xx(3),yy(3))

      to close

 

monitors

  contour(u)

 

plots

  surface(u)

  contour(u)

 

end