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From: Patrick Alken <patrick.alken@Colorado.EDU>
To: "gsl-discuss@sourceware.org" <gsl-discuss@sourceware.org>
Subject: Re: increment a single element of matrix/vector
Date: Tue, 28 Jan 2014 03:06:00 -0000	[thread overview]
Message-ID: <52E71EC5.800@colorado.edu> (raw)
In-Reply-To: <CAKDqugRJE8PbH8FTvzhi3LudALpopcsSq14aa1K-Rs5pXY36Gg@mail.gmail.com>

On 01/27/2014 07:14 PM, Rhys Ulerich wrote:
>> *gsl_vector_ptr(v, i) += x
> 
> Of course, make sure warnings about expressions without side effects
> are turned on.  Otherwise it may be a long debugging session before
> you discover a
> 
>     gsl_vector_ptr(v, i) += x
> 
> mistake for integer-like types.
> 
> - Rhys
> 

Nice find - unfortunately since it returns a pointer to the element, you
need to do:

*(gsl_vector_ptr(v, i)) += x;

This could lead to trouble so its probably better to have a function
which does range checking, etc. I'll think a little more on a good way
to do this.

Thanks,
Patrick

  reply	other threads:[~2014-01-28  3:06 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-01-27 23:47 Patrick Alken
2014-01-28  2:08 ` Rhys Ulerich
2014-01-28  2:15   ` Rhys Ulerich
2014-01-28  3:06     ` Patrick Alken [this message]
2014-01-28 20:45       ` Patrick Alken
2014-01-28 21:16         ` Rhys Ulerich
2014-01-28 21:26           ` Patrick Alken

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