# Changelog
All notable changes to this module (and sometimes relevant changes to other modules) will be documented in this file.

The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/)
but this project does not use [Semantic Versioning](http://semver.org/spec/v2.0.0.html).
Instead, version numbers indicate the year and month of release.



## [In current master]

### Added
- More integration tests for Flow, in particular for multisegment wells, solvent and polymer.

### Changed
- Refactoring: well models are now more independent and self-contained.
- Other minor refactoring: SimulatorBlackoilEbos::run().

### Fixed
- Fix bugs related to running Flow in parallel that caused slightly wrong results and bad performance in some cases, in particular the "model 2" case with 8 threads.

### Removed
- The ebos-based (i.e. using the new assembly approach) Flow variants as well as most of the legacy variants have been removed, use Flow instead.



## [2017.10] - 2017-10-31

### Added
- Added much-improved support for multisegment wells to Flow.
- Two-phase gas-oil cases are now supported in addition to water-oil (gas-water is still not supported).
- Added an experimental sequential splitting simulator using a reordering transport solver.

### Changed
- Major refactoring of well models.
- All Flow variant models have better performance. In particular this is significant for the two-phase, solvent and polymer variants, but also the basic black-oil model is faster.
- All Flow variants have now been collected in a single executable. The old, separate executables are still there, but will be removed.
- Improved log messages and reporting.
- Changed convergence testing for improved speed and stability control.
- Improved integration test coverage.
- Minor refactoring of several classes and systems.
- Build system fixes and cleanup.
- Improved Jenkins integration for data updating and static code analysis.
- Require Dune version at least 2.4, allow use of Dune 2.5.

### Fixed
- Fixed various minor bugs, including bugs in RESV controls, group controls, use of well efficiency factors, VFP treatment, fluid-in-place output.



## [2017.04] - 2017-04-26

### Added
- A Docker container has been created on Docker Hub, for easy deployment.
- Many more tests are now being run automatically to ensure correct simulator behaviour.

### Changed
- Flow now uses a new code for assembly of residuals and Jacobian matrices, resulting in significant performance gains. The new code is still based on automatic differentiation, but uses a more local approach than the previous method.
- Well handling has seen significant improvement, especially group controls. Flow is now able to correctly change well control depending on group limits in many cases previously not handled, although Flow still does not handle group control sets spanning more than two levels well. THP limits and VFP tables are handled in a more robust manner, and LRAT controls now work.
- Log output to PRT file and terminal is more precise, comprehensive and user friendly, with improved log messages and classification of messages. Timing and iteration reports have been cleaned up and now also include iterations that were wasted due to convergence failures. Also some minor output improvements for the 2-phase case have been made.
- Output possibilities for summary and restart files are now even more comprehensive, for example bubble point pressures can now be written. Restarting Flow simulations from restart files is improved, and reproduces initial runs much better than before.
- All grid-related parts of opm-core have been moved to the opm-grid module.
- Grids with inverted Z coordinates and left-handed coordinate system are now handled correctly.

### Fixed
- Many small bugs have been fixed. In total more than two hundred pull requests have been merged since last release.