Re: [AMBER-Developers] nofftw3 and MKL

From: Jason Swails <>
Date: Wed, 15 Oct 2014 23:18:52 -0400

> On Oct 15, 2014, at 10:26 PM, Scott Brozell <> wrote:
> Hi,
>> On Wed, Oct 15, 2014 at 03:51:41PM -0400, David A Case wrote:
>>> On Tue, Oct 14, 2014, Ross Walker wrote:
>>> Huh? - IANAL but seems to me that since we don't distribute any binaries
>>> and we require the user to build their own copy of AMBER that by doing so
>>> - that is manually running ./configure themselves and then typing make
>>> they are themselves manually linking to FFTW3 and we are not doing
>>> anything 'automatic' for them so this is probably not an issue.
>>> Comments?
>> I don't think you are a lawyer. And I don't think "automatic" vs.
>> "manual" is really important here. But I'd urge people to read paragraph
>> 4 of the GPLv3 license (in $AMBERHOME/AmberTools/LICENSE; this also
>> applies to fftw). All we are doing with fftw3 is distributing verbatim
>> source code, which is explicitly allowed. We never distribute non-source
>> code (covered by paragraph 6), so basically I think we are fine: remember
>> that the GPL rights are based on copyright. In this regard, GPLv3 is much
>> more explicit about what can and should not be done than is GPLv2.
> Wink, wink, nod, nod.
> ---
> tail $AMBERHOME/AmberTools/LICENSE
> The GNU General Public License does not permit incorporating your program
> into proprietary programs. If your program is a subroutine library, you
> may consider it more useful to permit linking proprietary applications with
> the library. If this is what you want to do, use the GNU Lesser General
> Public License instead of this License. But first, please read
> <>.
> ---
> And note that we are put into this position of saying
> "ohh, we didn't know that users would actually (illegally)
> link the fftw3 (that we legally distributed) with our proprietary programs"
> by lawyers:

There is nothing illegal about this. If users want to link free software they download with proprietary software they download that has a license permitting that use (like Amber does), that is perfectly acceptable. They are free to use free software however they like. The strictness in the GPL is just for relicensing and distributing... It's not at all restrictive for use.

What I'm not certain about is when do we cross the line of "the user is choosing to link fftw themselves by changing Amber" versus "we support fftw-enabled pmemd as a build option".

All the best,

Jason M. Swails
Rutgers University
Postdoctoral Researcher
AMBER-Developers mailing list
Received on Wed Oct 15 2014 - 20:30:02 PDT
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