From d068f0b3c11348a50c18af1ee3b0d2e5f38c4faf Mon Sep 17 00:00:00 2001
From: Matthew Sotoudeh <matthew@masot.net>
Date: Fri, 17 May 2024 15:57:30 -0700
Subject: lua benchmarks

---
 .../tests/Lua-Benchmarks/spectral-norm.lua         | 43 ++++++++++++++++++++++
 1 file changed, 43 insertions(+)
 create mode 100644 lua_benchmark/tests/Lua-Benchmarks/spectral-norm.lua

(limited to 'lua_benchmark/tests/Lua-Benchmarks/spectral-norm.lua')

diff --git a/lua_benchmark/tests/Lua-Benchmarks/spectral-norm.lua b/lua_benchmark/tests/Lua-Benchmarks/spectral-norm.lua
new file mode 100644
index 0000000..5ba652f
--- /dev/null
+++ b/lua_benchmark/tests/Lua-Benchmarks/spectral-norm.lua
@@ -0,0 +1,43 @@
+-- The Computer Language Benchmarks Game
+-- http://benchmarksgame.alioth.debian.org/
+-- contributed by Mike Pall
+
+local function A(i, j)
+  local ij = i+j-1
+  return 1.0 / (ij * (ij-1) * 0.5 + i)
+end
+
+local function Av(x, y, N)
+  for i=1,N do
+    local a = 0
+    for j=1,N do a = a + x[j] * A(i, j) end
+    y[i] = a
+  end
+end
+
+local function Atv(x, y, N)
+  for i=1,N do
+    local a = 0
+    for j=1,N do a = a + x[j] * A(j, i) end
+    y[i] = a
+  end
+end
+
+local function AtAv(x, y, t, N)
+  Av(x, t, N)
+  Atv(t, y, N)
+end
+
+local N = tonumber(arg and arg[1]) or 100
+local u, v, t = {}, {}, {}
+for i=1,N do u[i] = 1 end
+
+for i=1,10 do AtAv(u, v, t, N) AtAv(v, u, t, N) end
+
+local vBv, vv = 0, 0
+for i=1,N do
+  local ui, vi = u[i], v[i]
+  vBv = vBv + ui*vi
+  vv = vv + vi*vi
+end
+io.write(string.format("%0.9f\n", math.sqrt(vBv / vv)))
-- 
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