Merge pull request #228 from jdrugo/master

Add Gram-Schmidt orthonormalization to test view speed
JuliaCI · Sep 7, 2018 · 67af382 · 67af382
2 parents f2ca653 + cc77f64
commit 67af382
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diff --git a/src/array/ArrayBenchmarks.jl b/src/array/ArrayBenchmarks.jl
@@ -167,14 +167,21 @@ include("subarray.jl")
 
 n = samerand()
 
-g = addgroup!(SUITE, "subarray", ["lucompletepiv"])
+g = addgroup!(SUITE, "subarray", ["lucompletepiv", "gramschmidt"])
 
 for s in (100, 250, 500, 1000)
     m = samerand(s, s)
     g["lucompletepivCopy!", s] = @benchmarkable perf_lucompletepivCopy!(fill!($m, $n))
     g["lucompletepivSub!", s]  = @benchmarkable perf_lucompletepivSub!(fill!($m, $n))
 end
 
+# Gram-Schmidt orthonormalization, using views to operate on matrix slices.
+
+for s in (100, 250, 500, 1000)
+    m = samerand(s, s)
+    g["gramschmidt!", s] = @benchmarkable perf_gramschmidt!(fill!($m, $n))
+end
+
 #################
 # concatenation #
 #################

diff --git a/src/array/subarray.jl b/src/array/subarray.jl
@@ -45,3 +45,15 @@ function perf_lucompletepivSub!(A)
     end
     return (A, rowpiv, colpiv)
 end
+
+function perf_gramschmidt!(U)
+    m = size(U, 2)
+    @inbounds for k = 1:m
+        uk = view(U,:,k)
+        for j = 1:k-1
+            uj = view(U,:,j)
+            uk .-= (uj ⋅ uk) .* uj
+        end
+        uk ./= norm(uk)
+    end
+end