Add matmul sample

sample/matmul.cr

@@ -0,0 +1,45 @@
+# Copied with little modifications from: https://github.com/attractivechaos/plb/blob/master/matmul/matmul_v1.rb
+
+def matmul(a, b)
+  m = a.size
+  n = a[0].size
+  p = b[0].size
+  # transpose
+  b2 = Array.new(n) { Array.new(p, 0.0) }
+  (0...n).each do |i|
+    (0...p).each do |j|
+      b2[j][i] = b[i][j]
+    end
+  end
+  # multiplication
+  c = Array.new(m) { Array.new(p, 0.0) }
+  (0...m).each do |i|
+    (0...p).each do |j|
+      s = 0.0
+      ai, b2j = a[i], b2[j]
+      (0...n).each do |k|
+        s += ai[k] * b2j[k]
+      end
+      c[i][j] = s
+    end
+  end
+  c
+end
+
+def matgen(n)
+  tmp = 1.0 / n / n
+  a = Array.new(n) { Array.new(n, 0.0) }
+  (0...n).each do |i|
+    (0...n).each do |j|
+      a[i][j] = tmp * (i - j) * (i + j)
+    end
+  end
+  a
+end
+
+n = (ARGV[0]? || 500).to_i
+n = n / 2 * 2
+a = matgen(n)
+b = matgen(n)
+c = matmul(a, b)
+puts c[n / 2][n / 2]

sample/matmul.yml

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+name: http
+context:
+  crystal: crystal eval 'puts Crystal::VERSION'
+  host: uname
+measure:
+  - time
+  - cpu_time
+  - max_rss
+run: ./matmul $SIZE
+repeat: 3
+before: crystal build --release matmul.cr -o ./matmul
+after: rm -f ./matmul ./matmul.dwarf
+matrix:
+  env:
+    SIZE:
+      - 10
+      - 100
+      - 1000
+      - 2000