Hello,
I was testing if my code works with Clojure 1.1.0-alpha-SNAPSHOT - the
full code is attached to this group (in files section) as parallel-
factorial*.clj .
The code works in 1.0.0, but blows up in 1.1.0 for bigger numbers.
After a bit of digging, I found that following function is the culprit
(working version shown):
;----------------------
(defn part-num [#^Integer n #^Integer m]
(let [z (int (Math/floor (/ n m))) ; it generates float ranges
without the cast to int
last-range (range (+ (* z m) 1) (+ n 1))
]
(println z)
(println last-range)
(cons (if last-range last-range '(1))
(for [x (range m)]
(range (+ (* x z) 1) (+ (* (+ x 1) z) 1))
)
)
)
)
;----------------------
The problem is that without casting "z" to integer, the generated list
of ranges will have float numbers (and not integers), and that will
over-flow to infinity for large numbers when used in pfactorial
function.
No big deal, the fix is simple - this is heads up if more people find
their code broke with over-flow to infinity with the new version of
clojure.
It looks that float type "propagates" into arithmetics (and it did not
before) - better explanation welcome.
Kind regards,
Vladimir
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