Sample Problems > Usage > Functions > unit

{ UNIT_FUNCTIONS.PDE

This example illustrates the unit step, unit pulse,

and unit ramp functions ustep(arg1), upulse(arg1,arg2),

and uramp(arg1,arg2) See Unit Functions.

}

title

"unit functions"

select

elevationgrid=500

{no variables}

definitions

x1 = 0.2

x2 = 0.4

{no equations}

{plot domain -- required}

boundaries

region 1

start (-1,0)

line to (1,0) to (1,1) to (-1,1) to close

plots

elevation(ustep(x-x1)) from (0,0) to (1,0)

elevation(dx(ustep(x-x1))) from (0,0) to (1,0)

elevation(upulse(x-x1,x-x2)) from (0,0) to (1,0)

elevation(dx(upulse(x-x1,x-x2))) from (0,0) to (1,0)

elevation(uramp(x-x1,x-x2)) from (0,0) to (1,0)

elevation(dx(uramp(x-x1,x-x2))) from (0,0) to (1,0)

! generating a square wave by clipping a cosine

elevation(ustep(cos(4*pi*x))) from (-1,0) to (1,0)

! the duty cycle can be controlled by offsetting the cosine from zero

elevation(ustep(cos(4*pi*x)-0.3)) from (-1,0) to (1,0)

end

unit_functions