math.matrices: adding the outer product.

basis/math/matrices/matrices-docs.factor

@@ -22,3 +22,12 @@ HELP: kron
         "{ { 1 2 } { 3 4 } } { { 0 5 } { 6 7 } } kron ."
         "{ { 0 5 0 10 } { 6 7 12 14 } { 0 15 0 20 } { 18 21 24 28 } }" }
 } ;
+
+HELP: outer
+{ $values { "u" sequence } { "v" sequence } { "m" sequence } }
+{ $description "Computers the outer product of " { $snippet "u" } " and " { $snippet "v" } "." }
+{ $examples
+    { $example "USING: math.matrices prettyprint ;"
+        "{ 5 6 7 } { 1 2 3 } outer ."
+        "{ { 5 10 15 } { 6 12 18 } { 7 14 21 } }" }
+} ;

basis/math/matrices/matrices-tests.factor

@@ -276,3 +276,9 @@ IN: math.matrices.tests
     { { 1 1 } { 1 -1 } }
     { { 1 2 3 4 5 } { 6 7 8 9 10 } } swap kron
 ] unit-test
+
+{
+    { { 5 10 15 }
+      { 6 12 18 }
+      { 7 14 21 } }
+} [ { 5 6 7 } { 1 2 3 } outer ] unit-test

basis/math/matrices/matrices.factor

@@ -165,3 +165,6 @@ IN: math.matrices
 
 : kron ( m1 m2 -- m )
     '[ [ _ n*m  ] map ] map stitch stitch ;
+
+: outer ( u v -- m )
+    [ n*v ] curry map ;