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local Complex={type="package"}
local function complex(x,y)
return setmetatable({ re=x, im=y }, Complex.metatable)
end
function Complex.conj(x,y)
return complex(x.re,-x.im)
end
function Complex.norm2(x)
local n=Complex.mul(x,Complex.conj(x))
return n.re
end
function Complex.abs(x)
return sqrt(Complex.norm2(x))
end
function Complex.add(x,y)
return complex(x.re+y.re,x.im+y.im)
end
function Complex.mul(x,y)
return complex(x.re*y.re-x.im*y.im,x.re*y.im+x.im*y.re)
end
Complex.metatable={
__add = Complex.add,
__mul = Complex.mul,
}
local function abs(x)
return math.sqrt(Complex.norm2(x))
end
xmin=-2.0 xmax=2.0 ymin=-2.0 ymax=2.0
N=arg[1] or 256
function level(x,y)
local c=complex(x,y)
local l=0
local z=c
repeat
z=z*z+c
l=l+1
until abs(z)>2.0 or l>255
return l-1
end
dx=(xmax-xmin)/N
dy=(ymax-ymin)/N
print("P2")
print("# mandelbrot set",xmin,xmax,ymin,ymax,N)
print(N,N,255)
local S = 0
for i=1,N do
local x=xmin+(i-1)*dx
for j=1,N do
local y=ymin+(j-1)*dy
S = S + level(x,y)
end
-- if i % 10 == 0 then print(collectgarbage"count") end
end
print(S)
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