Gvar

==========================

The biggest change in this version is that gvar is now distributed
independently of lsqfit; it will no longer be bundled with the latter. This
is better because gvar is used by packages other than lsqfit. There are also
two very minor but incompatible changes, in the interfaces for gvar.chi2 and
gvar.ode, that require the major version number to increase from 6 to 7
(because of semantic versioning). Finally there are some significant
additions to the numerical analysis routines provided with gvar.

- The first incompatible change concerns a rarely used feature
of gvar.chi2. Previous versions stored information about dof and Q in
as attributes of the function; these are now stored in the result of the
function, which is much more natural.

- The second incompatible change is in gvar.ode. The behavior when the
step size is reduced below hmin is changed. Before an exception was
issued and execution stopped. Now a warning is issued, the step size
is not reduced and execution continues. The warning is necessary since
it means that errors may not be under control to the extent hoped.

- Added gvar.ode.integral for 1d integrals.

- Added two new numerical analysis packages to gvar:

gvar.root - finds roots of 1d functions
gvar.linalg - basic linear algebra (det, inv, solve, eigvalsh ...)

As for the other numerical analysis methods, the new methods work with any
combination of numbers and GVars.

- gvar.cspline now allows you to specify what order polynomial is used for
out-of-range points. In the past a cubic polynomial was used, based on
the value and derivatives at the knot nearest to the out-of-range point.
Now one can specify a lower-order polynomial by setting parameter
extrap_order equal to 0, 1, or 2.

- Added gvar.equivalent(g1, g2, rtol, atol) which checkes whether or not
the GVars in g1 and g2 are the equivalent (ie, g.mean and g.der agree
for each GVar). This is useful for debugging purposes.

- Installation will now use setuptools instead of disutils, provided
setuptools is installed. setuptools automatically ensures that
modules needed by gvar are installed and sufficiently
up-to-date. If setuptools is not installed, distutils is used and
dependencies are not checked --- this must be done by hand.

- Tiny addition to gvar tests.

========================

This upgrade deals with some issues created by the most recent update to
numpy (v1.9.0). The verion number increases to 6 because a (very minor) part
of the gvar.powerseries interface had to change (and therefore by the rules of
semantic versioning one must increase the major verion number). BufferDicts
are also subtly changed, though in a way that shouldn't affect much code.
A couple of enhancements are included as well.

- gvar.BufferDicts are now derived from collections.OrderedDict. This is
a consequence of the numpy change, but it is probably a good idea anyway.
The interface is the same but pickling has changed. This means that
BufferDicts pickled with the old software cannot be unpickled with
the new. A very minimal module, oldbufferdict.py, is included in lsqfit
for converting old pickled data to the new format; see documentation
inside the file. Data stored using json is unaffected.

- The power series coefficents of gvar.powerseries.PowerSeries variable
p are now accessed via attribute c: p.c[0], p.c[1] etc. Formerly one
could access the coefficients using array notation --- p[0] for p.c[0],
etc --- but this no longer works with numpy. The old notation was a bad
idea in any case.

- gvar.fmt_errorbudget has a new option called verify. Set verify=True
to have the code check that the error budget is complete and has no
double counting of errors; a warning is issued if this is not the case.

- Added arctan2 to the list of functions that work with GVars,
using code from Matt Wingate. (NB, the documentation shows how to
create additional functions (eg, erf(x)) using gvar_function.)

- Obscure bug fix in gvar.ode.Integrator allows GVars as the
independent variables.

- Rearranged documentation now includes case studies. These are self
contained examples that are extensively annotated (and relatively simple).
There are only two at the moment but more are forthcoming.

===========================
This is a very minor bug fix.

- Modified gvar.mean(g), gvar.sdev(g), gvar.var(g) so that g can
include elements that are not GVars. These elements are assumed to
have zero error, so their value is their mean. This means, for
example, that g can be all GVars or all floats or a mixture.

- Fixed bug in gvar.ranseed which caused it to crash under python3 in
certain circumstances.

=========================
A minor upgrade to provide functionality for other libraries. The first
change is not backwards compatible, but is unlikely to break much or any
code (except mine).

- fit.svdcorrection is now the sum of all svdcorrections, not a vector. The
sum is all that is needed to construct error budgets, which is the
only use for fit.svdcorrection. The sum is easier to manipulate -- for
example, two svdcorrections can now be added to give a composite
svdcorrection (as opposed to concatenated before).

- Fixed innocuous bug in lsqfit.nonlinear_fit.format().

- gvar.dataset.Dataset.slice can now apply slices to multiple dimensions.

- Added __format__ to gvar.GVar. This converts the GVar to a string
and then applies the format to the string. This was needed to make
python3 and python2 function similarly in certain situations.

- More polishing of the documentation (especially about svd).

- Beginning with this version of lsqfit, version numbers will be consistent
with the rules of "semantic versioning" (http://semver.org). The most
important consequence is that any change that is *not* backwards compatible
with the current interface (as defined by the documentation) will be signaled
by a change in the major version number, where the full version number has the
format major.minor.patch (so the major version number is 5 for version 5.0).
A side effect of this is that increases in the major version number can
be triggered by relatively obscure changes in the interface that will have
no effect whatsoever on almost all existing codes. The current move to 5.0
is an example.

============================
This release is almost identical to the previous release. It is mainly to do
with getting the software registered properly online.

- Small improvement to the user interface in gvar.ode. It now works with
vectors of x values, returning vectors of y values.

==========================

- Bug fix so recent changes in lsqfit don't cause crashes on Windows systems.