QMCPACK Release v4.2.0 - 2026-02-12

Download QMCPACK v4.2.0

Notes

This release is recommended for all users and includes several new features, improved GPU support, a broad range of other useful improvements, and compatibility and bug fixes. NEXUS also receives significant updates including a packaging update to make it function as a conventional Python package (requiring an update PYTHONPATH).

  • Upcoming breaking change: Classic/non-batched drivers will be removed in a future release. See https://qmcpack.readthedocs.io/en/develop/performance_portable.html for instructions on using the batched/performance portable drivers. New projects should only use the batched drivers.
  • Added new variable period for estimator measurements feature, input parameter estimator_period, and Nexus support #5574, #5577. Substantial speed and efficiency improvements are possible for properties with a long autocorrelation period.
  • GPU offload of SOC calculations completed #5547
  • Batched implementation of G of r ( g(r), PairCorrEstimator ) #5600
  • Batched structure factor estimator #5490, #5540
  • Orbital rotation support for fully complex wavefunctions on GPUs #5549
  • Support for ROCm 7.0+ #5548
  • Container with "complete" QMCPACK development version including Quantum ESPRESSO and PySCF #5681, #5782. This will be expanded and documented in future versions.
  • bandinfo.dat files are now consistently named by their SPOset and not einspline #5785
  • Bug fix to three-body Jastrow GPU implementation (caused rare GPU crash) #5546
  • Docs for QP2 plugin installation requirement #5667
  • Docs for timers #5486
  • Docs for qmc-get-supercell tool. #5611
  • Added 2dxy option to qmc-get-supercell tool #5607
  • Add symmetry support for PySCF multiconfiguration methods to savetoqmcpack #5564
  • Initial python coverage reporting #5751
  • Reduced use of python pandas in tests #5732
  • Alignment fixes for CUDA complex host scalars #5760
  • Improved Aurora/Intel GPU LCAO performance #5533
  • Added benchmark tests for batched BLAS routines #5591
  • Added SYCL benchmark for SolverInverters #5493
  • Expanded LMY engine configuration messages #5488
  • Improvements to build process, testing, and fixing of minor bugs.

Known issues:

  • Multireference/multideterminant wavefunctions from PySCF and GAMESS are reported as not correctly converted #5563, #5789. Due to the widespread use of multideterminants in QMC, where no issues have been reported, we currently believe the problems to be fully related to the export and conversion of multideterminant wavefunctions from these codes.
  • Backflow wavefunctions are not working for ab initio (vs model) Hamiltonians in the batched drivers #5459
  • The energy density estimator is incorrect #5468
  • AFQMC utilities and converters are not compatible with modern PySCF #4653

NEXUS [2.2.0]

  • Refactored so that it can be used as a conventional Python package. PYTHONPATH should now point to the topmost nexus directory, not nexus/lib. #5700
  • New releases will be consistently versioned with the major, minor and patch number updated following semantic versioning.
  • Important fix for XML text parsing for non-uniform lists of numeric types. A list such as [0 0 0.1] could previously be misread #5756
  • New spin resolved lineplot capability in qdens #5662
  • New capability to modify existing QMCPACK input files #5631
  • Support for custom commands/scripts as simulation objects #5613
  • Support opt.vp.h5 files and stochastic reconfiguration input generation #5580
  • Support for override_variational_parameters in QMCPACK dependencies #5713
  • Added Leonardo (CINECA) machine #5759
  • Added Frontier (ORNL) support #5519
  • Added Aurora (ANL) support #5517
  • Updated and revised definitions for existing machines, e.g. #5661
  • Improve Structure.center_molecule() to ensure equal vacuum padding on all sides #5617
  • Docs for controlling bundled twist averaged calculations #5722
  • Docs for Quantum ESPRESSO DFT+U format #5710
  • Docs for code style #5679
  • Docs for job bundling using nexus. #5670
  • Updated GCTA example to QE 7.1 DFT+U format #5691
  • Fixed python syntax format warnings e.g. #5795, #5779
  • Fixed Structure.recenter_k() and Structure.recenter() #5664
  • Matplot compatibility improved #5622
  • Updated Numpy array shaping to comply with deprecation in Numpy 2.5 #5757
  • Removed Structure.magnetize() #5766