Hello, this is on clisp 2.48 on cygwin. The function low-discrepancy-sample could not compile because iterate could not digest loop ***** Iterate, in clause (COLLECT (APPLY MAKE-FUNCTION (APPEND FIXED-PARAMETERS (MAPCAN (LAMBDA (X SEQ) (LIST (FIRST X) (VAL-FROM-RANGE (GREF V SEQ) (SECOND X) (THIRD X)))) SWEEP-PARAMETERS (LOOP FOR I FROM 0 BELOW (LENGTH SWEEP-PARAMETERS) COLLECT I))))): Iterate does not know how to handle the special form (MACROLET ((LOOP-FINISH NIL (SYSTEM::LOOP-FINISH-ERROR))) (BLOCK NIL (LET ((I 0) (#:LIMIT-273656 (LENGTH SWEEP-PARAMETERS))) (PROGN (LET ((#:ACCULIST-VAR-273657 NIL)) (MACROLET ((LOOP-FINISH NIL '(GO SYSTEM::END-LOOP))) (TAGBODY SYSTEM::BEGIN-LOOP (WHEN (COMMON-LISP:>= I #:LIMIT-273656) (LOOP-FINISH)) (PROGN (SETQ #:ACCULIST-VAR-273657 (CONS I #:ACCULIST-VAR-273657))) (PSETQ I (COMMON-LISP:+ I 1)) (GO SYSTEM::BEGIN-LOOP) SYSTEM::END-LOOP (MACROLET ((LOOP-FINISH NIL (SYSTEM::LOOP-FINISH-WARN) '(GO SYSTEM::END-LOOP))) (RETURN-FROM NIL (SYSTEM::LIST-NREVERSE #:ACCULIST-VAR-273657)))))))))) It will not be walked, which means that Iterate clauses inside it will not be seen. ***** If I replaced the loop form with the much more verbose (let (res) (dotimes (i (length sweep-parameters) (nreverse res)) (push i res))) the code compiled cleanly. The same error can be seen with a much simpler: (iter:iter (iter:for v iter:in '(1 2 3 4)) (iter:collect (loop for i in v))) Another alternative is to use iter instead of loop (iter:iter (iter:for i from 0 below (length sweep-parameters)) (iter:collect i)) It compiles cleanly, but I did not test the function accuracy. Mirko