# What’s New in Halotools v0.6?¶

Halotools `v0.6`

is now available for installation with conda and pip. New features are summarized below. See Full Changelog for details on smaller issues and bug-fixes. See Version v0.x release history for full release history information.

## Quick Installation Verification¶

It is now much faster to verify successful installation of the latest version of halotools. After installing the code, you can now run a targeted subset of unit tests, rather than the entire test suite:

```
import halotools
halotools.test_installation()
```

## New Mock Observables¶

### Radial distances and velocities¶

There are new functions in the `mock_observables`

sub-package that calculate element-wise radial distances and velocities, `radial_distance`

and `radial_distance_and_velocity`

.

### Jackknife error estimation¶

New functions `wp_jackknife`

and `rp_pi_tpcf_jackknife`

give jackknife error estimation for the `wp`

and `rp_pi_tpcf`

functions.

### Weighted pair counts as a function of (s, mu)¶

New `halotools.mock_observables.pair_counters.weighted_npairs_s_mu`

function gives weighting option for counting pairs in (s, mu) space.

## Utility functions¶

### Matching two distributions for statistical comparison¶

The `halotools.utils.distribution_matching_indices`

function Monte Carlo resamples one distribution until it matches another.

## API Change¶

- The
`npairs_s_mu`

function now has a change to the meaning of the`mu_bins`

input argument. This argument should now be interpreted as the conventional mu=cos(theta_LOS) instead of mu=sin(theta_LOS).