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array_boundary

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array_boundary

{ ARRAY_BOUNDARY.PDE

This problem demonstrates the use of data ARRAYS in boundary definition.

Coordinate arrays are constructed by functional array definition

and joined in a spline fit to form the system boundary.

}

title 'ARRAY_BOUNDARY test'

variables

u

definitions

a = 1

! construct x and y coordinates on a semicircle

xb =array for ang(-pi/2 by pi/10 to pi/2)  : rad*cos(ang)

yb =array for ang(-pi/2 by pi/10 to pi/2)  : rad*sin(ang)

! multiplying an array by a constant

xba = 10*xb

yba = 10*yb

! adding a constant to an array

xbb = xba+11

s = 1

equations

u:  div(a*grad(u)) + s  = 0;           { a heatflow equation }

boundaries

region 1       { a half-circle built of line segments }

value(u)=0

line list (xba, yba)

natural(u)=0

line to close

region 2       { a half-circle built of spline segments }

value(u)=0

spline list (xbb, yba)

natural(u)=0

line to close

plots

grid(x,y)

contour(u) painted

surface(u)

end