Message-ID: <CAFDcVCSe+tp=aW=xoVXW2p3eUuj6HKer6jd-e+86FHEG0LBdRw@mail.gmail.com>
Date: 2015-01-02T20:00:08Z
From: Henrik Bengtsson
Subject: Benchmark code, but avoid printing
In-Reply-To: <CABtg=KmgV-6QEffrGc4HzOSUM-jvE3ExHFB1KefAgv16S=+oGA@mail.gmail.com>
On Fri, Jan 2, 2015 at 9:02 AM, G?bor Cs?rdi <csardi.gabor at gmail.com> wrote:
> Dear all,
>
> I am trying to benchmark code that occasionally prints on the screen
> and I want to
> suppress the printing. Is there an idiom for this?
>
> If I do
>
> sink(tempfile)
> microbenchmark(...)
> sink()
>
> then I'll be also measuring the costs of writing to tempfile. I could
> also sink to /dev/null, which is probably fast, but that is not
> portable.
Interesting problem. On Windows NUL corresponds to /dev/NULL, e.g.
con <- file("NUL", open="wb"). Not that it's cross platform, but it
at least allows you to cover on more OS. Maybe R should have a
built-in "null" device. An easier solution is probably to go back to
the maintainers of the functions outputting text and ask them for an
option to disable that.
>
> Is there a better solution? Is writing to a textConnection() better?
For large number of output *lines* (not characters), textConnection()
is exponentially slow (at least in R 3.1.0). Use rawConnection()
instead, cf. http://www.jottr.org/2014/05/captureOutput.html
/Henrik
>
> Thanks, Best,
> Gabor
>
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