Chebfun v5.2.0 Released

[Anthony Austin]

We are pleased to announce the release of Chebfun Version 5.2.0 for
numerical computing with 1D and 2D functions. The main new features are:

* A fast implementation of the discrete Legendre transform (DLT) and its
inverse (IDLT).

* epslevel accuracy estimates have been disabled (fixed at machine
epsilon and no longer displayed when printing a `chebfun`).

* Automatic vectorization for anonymous functions used to specify chebop
operators and boundary conditions. For example, `N.op = @(x,u)
x.*diff(u) + u.^2` can now be replaced by `N.op = @(x,u) x*diff(u) + u^2`.

* `chebop` `null` method for systems of equations.

* `pde23t`, significantly faster than `pde15s` for non-diffusive PDEs.
`pde23t` is now also an option in `chebgui`.

* Periodic discretization of periodic PDEs in `pde15s` and `pde23t`
(specify boundary conditions as 'periodic').

* Minimax approximation of periodic functions via `trigremez`.

* Support for fractional integrals and derivatives of smooth chebfuns,
by passing non-integer arguments to `diff` and `cumsum`.

In addition, significant speed-ups have been achieved for evaluation of
`chebfun2` objects, QR factorizations of tall and skinny quasimatrices,
piecewise ODEs and for solving PDEs in `chebgui`. Finally, various bugs
have been fixed and documentation has been improved.

We hope you enjoy the new release. Feel free to contact us at
<he...@chebfun.org> if you have any questions or comments.