math.extras: adding logspace.

extra/math/extras/extras-docs.factor

@@ -61,3 +61,7 @@ HELP: sinc
 HELP: linspace
 { $values { "from" number } { "to" number } { "points" number } { "seq" sequence } }
 { $description "Return evenly spaced numbers over a specified interval " { $snippet "[from,to]" } "." } ;
+
+HELP: logspace
+{ $values { "from" number } { "to" number } { "points" number } { "base" number } { "seq" sequence } }
+{ $description "Return evenly spaced numbers on a log scaled interval " { $snippet "[base^from,base^to]" } "." } ;

extra/math/extras/extras.factor

@@ -201,3 +201,6 @@ PRIVATE>
 
 : linspace ( from to points -- seq )
     1 - [ 2dup swap - ] dip / <range> ;
+
+: logspace ( from to points base -- seq )
+    [ linspace ] dip swap n^v ;