Graphics Programs Reference
In-Depth Information
The darkest spots in the room have intensity around 0.93, as opposed to 0.63
for a single bulb. This represents an improvement of about 50%.
Three 100-Watt Bulbs
We redefine the intensity function for 100-watt bulbs:
light3 = inline(vectorize('100/(4*pi*((x - d)ˆ2 + (y - 2)ˆ2 +
3ˆ2))'), 'x', 'y', 'd')
light3 =
Inline function:
light3(x,y,d) = 100./(4.*pi.*((x - d).ˆ2 + (y - 2).ˆ2 +
3.ˆ2))
Assume we put one bulb at the center of the room and place the other two
symmetrically as before. Here we show the illumination of the floor when the
off-center bulbs are one meter from the short walls.
[X,Y] = meshgrid(0:0.1:10, 0:0.1:4); contourf(light3(X, Y, 1)
+ light3(X, Y, 5) + light3(X, Y, 9), 20);
axis equal tight
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It appears that we should put the bulbs even closer to the walls. (This may
not please everyone's aesthetics!) Let
d
be the distance of the bulbs from the
short walls. We define a function giving the intensity at position
x
along a
long wall and then graph the intensity as a function of
d
for several values
of
x
.
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