Merge pull request #324 from JuliaArrays/fix-nonsquare-matrix-mult

Fix sizes in non-square medium sized matrix multiply

Author: c42f

src/matrix_multiply.jl

@@ -207,9 +207,11 @@ end
     S = Size(sa[1], sb[2])
 
     # Do a custom b[:, k2] to return a SVector (an isbits type) rather than (possibly) a mutable type. Avoids allocation == faster
-    tmp_type_in = :(SVector{$(sa[1]), T})
-    tmp_type_out = :(SVector{$(sb[1]), T})
-    vect_exprs = [:($(Symbol("tmp_$k2"))::$tmp_type_out = partly_unrolled_multiply(Size(a), Size($(sa[1])), a, $(Expr(:call, tmp_type_in, [Expr(:ref, :b, sub2ind(S, i, k2)) for i = 1:sb[1]]...)))::$tmp_type_out) for k2 = 1:sb[2]]
+    tmp_type_in = :(SVector{$(sb[1]), T})
+    tmp_type_out = :(SVector{$(sa[1]), T})
+    vect_exprs = [:($(Symbol("tmp_$k2"))::$tmp_type_out = partly_unrolled_multiply(Size(a), Size($(sb[1])), a,
+                    $(Expr(:call, tmp_type_in, [Expr(:ref, :b, sub2ind(sb, i, k2)) for i = 1:sb[1]]...)))::$tmp_type_out)
+                  for k2 = 1:sb[2]]
 
     exprs = [:($(Symbol("tmp_$k2"))[$k1]) for k1 = 1:sa[1], k2 = 1:sb[2]]
 

test/matrix_multiply.jl

@@ -121,6 +121,14 @@
         n2 = SMatrix{16,16}(n_array2)
         @test m2*n2 === SMatrix{16,16}(a_array2)
 
+        # Non-square version
+        m_array3 = rand(1:10, 9, 10)
+        n_array3 = rand(1:10, 10, 11)
+        a_array3 = m_array3*n_array3
+        m3 = SMatrix{9,10}(m_array3)
+        n3 = SMatrix{10,11}(n_array3)
+        @test m3*n3 === SMatrix{9,11}(a_array3)
+
         # Mutating types follow different behaviour
         m_array = rand(1:10, 10, 10)
         n_array = rand(1:10, 10, 10)