Cast to Real in C++ style throughout

Cast to Real in C++ style throughout

[Dan Eble, 2020-02-02 18:51:08]

LGTM

https://codereview.appspot.com/547560044/diff/555240043/lily/spring.cc
File lily/spring.cc (right):

https://codereview.appspot.com/547560044/diff/555240043/lily/spring.cc#newcod...
lily/spring.cc:119: avg_stretch /= static_cast<Real> (springs.size ());
This is not an issue with this change, but should this function do something
other than divide by zero when springs is empty?

[dak, 2020-02-02 19:08:59]

On 2020/02/02 18:51:08, Dan Eble wrote:
> LGTM
> 
> https://codereview.appspot.com/547560044/diff/555240043/lily/spring.cc
> File lily/spring.cc (right):
> 
>
https://codereview.appspot.com/547560044/diff/555240043/lily/spring.cc#newcod...
> lily/spring.cc:119: avg_stretch /= static_cast<Real> (springs.size ());
> This is not an issue with this change, but should this function do something
> other than divide by zero when springs is empty?

Possibly.  We have had a few reports of combinations of forced breaks leading to
failed assertions.  Dividing by Real zero (which was done here before as well
due to conversion rules) does not throw divide-by-zero but results in ±inf.0
(unless the numerator is also zero, then you get ±nan.0).  So I won't rule out
that some of the triggering cases might have come through this code path.

[hanwenn, 2020-02-02 20:00:36]

https://codereview.appspot.com/547560044/diff/555240043/lily/spring.cc
File lily/spring.cc (right):

https://codereview.appspot.com/547560044/diff/555240043/lily/spring.cc#newcod...
lily/spring.cc:119: avg_stretch /= static_cast<Real> (springs.size ());
On 2020/02/02 18:51:08, Dan Eble wrote:
> This is not an issue with this change, but should this function do something
> other than divide by zero when springs is empty?

what is the average of an empty set of numbers?

the 2 callers use a fallback in case there are not springs.