Randomness in Madeup
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About 30% into writing tests for a piece of code, my energy deflates. When I consider how many more tests I have to write to thoroughly test my code, I am overwhelmed. The worst part about testing is that you can’t just tax the moving parts of your software the way someone like you would. You have to step into the mind of your most incompetent user. I’m guessing criminal investigators face a similar problem when hunting down a homicidal maniac. Both of us have to twist our brain into thinking irrational and perverse thoughts to crack the case.
I then decide that the best thing for me to do is randomly generate a bunch of input data and see how my software handles it. That’s what I can do now in Madeup: generate random data. Two new constructs exist: a special seed variable and a random function:
seed = 10 -- chooses random sequence 10 n = random lo hi -- get a random number from [lo, hi]
If the seed is not set by the user, the current clock value is used.
I offer a few examples of random’s use.
Random Dots
A collection of randomly-placed and randomly-sized spheres.
nsides = 30 repeat 150 radius = random 1 3 x = random -10 10 y = random -10 10 z = random -10 10 moveto x y z end dots
Random Top
A vertical 10-node tube with each node assigned a random radius.
moveto 0 0 0 seed = 10 nsides = 40 repeat 10 radius = random 1 5 move 1 end tube
Random Strand
A strand generated from a random 3-D walk.
moveto 0 0 0
nsides = 10
radius = 4
seed = 27
repeat 300
dimension = random 0 2
angle = random 50 70
if dimension == 0
yaw angle
else
if dimension == 1
pitch angle
else
roll angle
end
end
move (random 1 3)
end
dots
Random Terrain
Rocky terrain generated by perturbing the nodes of a 50×50 grid by some random amount.
size = 50
seed = 60
for r to size
for c to size
moveto c r 0.5 * (random -1 1)
end
end
surface size size