math.finance: Removing an instance of "spin".

extra/math/finance/finance-tests.factor

@@ -2,6 +2,8 @@ USING: kernel math math.functions math.finance tools.test ;
 
 IN: math.finance.tests
 
+[ { 1 2 3 4 } ] [ { 1 2 3 4 5 } 1 ema ] unit-test
+
 [ { 2 4 } ] [ { 1 3 5 } 2 sma ] unit-test
 
 [ { 1 3 1 } ] [ { 1 3 2 6 3 } 2 momentum ] unit-test

extra/math/finance/finance.factor

@@ -15,7 +15,7 @@ IN: math.finance
 PRIVATE>
 
 : ema ( seq n -- newseq )
-    a swap unclip [ [ dup ] 2dip spin weighted ] accumulate 2nip ;
+    a swap unclip [ swap pick weighted ] accumulate 2nip ;
 
 : sma ( seq n -- newseq )
     clump [ mean ] map ;