73 lines
1.2 KiB
Lua
73 lines
1.2 KiB
Lua
--[[
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The Great Computer Language Shootout
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http://shootout.alioth.debian.org/
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contributed by Ian Osgood
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]]
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local bench = script and require(script.Parent.bench_support) or require("bench_support")
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function test()
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function A(i,j)
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return 1/((i+j)*(i+j+1)/2+i+1);
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end
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function Au(u,v)
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for i = 0,#u-1 do
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local t = 0;
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for j = 0,#u-1 do
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t = t + A(i,j) * u[j + 1];
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end
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v[i + 1] = t;
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end
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end
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function Atu(u,v)
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for i = 0,#u-1 do
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local t = 0;
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for j = 0,#u-1 do
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t = t + A(j,i) * u[j + 1];
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end
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v[i + 1] = t;
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end
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end
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function AtAu(u,v,w)
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Au(u,w);
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Atu(w,v);
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end
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function spectralnorm(n)
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local u, v, w, vv, vBv = {}, {}, {}, 0, 0;
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for i = 1,n do
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u[i] = 1; v[i] = 0; w[i] = 0;
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end
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for i = 0,9 do
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AtAu(u,v,w);
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AtAu(v,u,w);
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end
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for i = 1,n do
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vBv = vBv + u[i]*v[i];
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vv = vv + v[i]*v[i];
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end
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return math.sqrt(vBv/vv);
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end
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local total = 0;
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local i = 6
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while i <= 48 do
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total = total + spectralnorm(i);
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i = i * 2
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end
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local expected = 5.086694231303284;
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if (total ~= expected) then
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assert(false, "ERROR: bad result: expected " .. expected .. " but got " .. total)
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end
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end
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bench.runCode(test, "math-spectral-norm")
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