2026 Apr Monthly Update

Release Notes

1. Expanded Molecular Dynamics Workflow

MAPLE now extends beyond the original NVE workflow with experimental NVT and NPT support. This release adds Langevin and V-rescale thermostats, Berendsen and C-rescale barostats, improved thermodynamic logging, restartable trajectories, and final.xyz structure export. @AxiEj

2. GROMACS-style MDP Input and MD Template Generation

MD jobs can now be configured through GROMACS-style .mdp files and generated directly from the command line with maple md. This makes it easier to prepare standard NVE, NVT, and NPT workflows with more reproducible settings.

3. Restart, Checkpoint, and Trajectory Output Improvements

Added rst_file-based restart support across MD workflows, cleaner cross-ensemble restart handling, RNG state persistence in restart files, and binary DCD trajectory output for more efficient storage and post-processing.

4. Periodic Boundary Condition and File Handling Improvements

Periodic workflows have been cleaned up with more consistent handling of structure files, trajectory inputs, and relative paths. XYZ / XYZTRAJ references and restart file resolution now behave more robustly from the output directory.

5. UMA Task Sizing and MACEPol Integration

Added task-aware UMA size selection together with broader fallback checkpoint support for uma-s-1p1, uma-s-1p2, and uma-m-1p1. This release also introduces MACEPol integration and related example inputs.

6. IRC Improvements and Debugging Cleanup

Merged IRC-related updates and debugging work into the release branch, including parser stabilization, workflow cleanup, and general fixes around reaction path and transition-state related execution. @AmiHaruka

7. CLI and Input Handling Improvements

Added --version support on the command line and improved inline coordinate parsing, log method behavior, and general input handling consistency across the enhance branch.

8. Examples, Utilities, and Developer Documentation

Expanded MD and model examples, refreshed project architecture notes, and updated utility scripts for trajectory analysis, drift plotting, and supporting workflow generation.

- Bug Fixes

Fixed inline coordinates parsing and log method issues.
Improved restart file path handling from output directories.
Expanded UMA fallback handling across supported checkpoint variants.
Included general IRC and debug fixes from the enhance line.

- Notes

NVT and NPT are included in this release but should still be considered experimental while validation against reference implementations continues.

2026 Feb Monthly Update

Release Notes

1. AutoNEB: Automated Multi-step Reaction Pathway Exploration

Tree-based automated NEB that detects intermediate minima, splits paths into sub-segments, and recursively optimizes each branch. Supports adaptive image insertion, endpoint optimization, and final global MEP refinement.

2. NVE Molecular Dynamics Module

New classical molecular dynamics simulation using Velocity Verlet integration in the microcanonical (NVE) ensemble. Includes Maxwell-Boltzmann velocity initialization, thermodynamic logging, and XYZ trajectory output.

3. SDCG Fusion Optimizer

Phased geometry optimization combining Steepest Descent (robust initial approach) with PRP+ Conjugate Gradient (faster convergence near minimum). Includes GDIIS (Geometry DIIS) acceleration using Barzilai-Borwein step estimation. Users can select SD-only, CG-only, or the default SD+CG fusion mode.

4. Three New IRC Integrators: EulerPC, HPC, LQA

Added Euler Predictor-Corrector, Hessian-based Predictor-Corrector, and Local Quadratic Approximation IRC methods, all operating in mass-weighted coordinates with Bofill/BFGS Hessian updates and DWI+mBS corrector integration for EulerPC/HPC. @AmiHaruka

4. Rigid Scan Mode

Scan module now supports rigid body scans alongside relaxed scans. Fragment groups are automatically detected from bond connectivity, enabling efficient potential energy surface exploration without optimization at each grid point. @AmiHaruka

6. Trajectory Single Point Calculations

Single point calculations can now process multiple structures from trajectory files or multi-structure inputs. Three verbosity levels control output detail from energy-only to full coordinates.

7. Charge/Multiplicity Inline Input & Compatibility Warnings

Coordinate groups now accept an optional charge multiplicity line before atomic coordinates. The calculator initialization detects non-default charge/mult and warns when the selected ML model (e.g., ANI, MACE-OFF) does not support these parameters.

8. GDIIS Accelerator Rewrite

The DIIS module has been rewritten as a proper GDIIS (Geometry DIIS) accelerator following Csaszar-Pulay/Farkas-Schlegel formulations. Uses corrected coordinates (x_tilde = x + step_scale * f) instead of naive coordinate extrapolation, with Tikhonov regularization for numerical stability.

9. Centralized Parameter Handling via JobABC

All job classes now inherit a unified _init_params() method that maps user-provided dictionaries to typed dataclass parameters with case-insensitive key matching and sub-dictionary extraction. Reduces boilerplate and ensures consistent parameter parsing across all modules.

- Bug Fixes

Fixed dimer method trajectory output and TS geometry writing.
Fixed CI-NEB force projection and climbing image convergence checks.
Cleaned up and standardized example directory, removing large unused scan examples.

- Documentations
MAPLE Website Development (https://www.maplechem.org/) @Carlo8910 @charleszrz
OPT tutorial @AxiEj
IRC tutorial @AmiHaruka

v.0.1.0

Fundamental Implementation of MAPLE