layout: releases title: “” nav_title: “Release v2.3.0” permalink: /releases/v2.3.0/ nav_exclude: true sitemap: false —

Release v2.3.0

Release Date: March 17, 2026

This is a major release that introduces a number of new features, but mainly a massive change to internal modernization of the codebase. Plus, we are now wrapping SimNIBS 4.6.0.

New Features

  • Combined ROI Analysis: You can now select multiple atlas regions to analyze as a single combined ROI. Pass a list of region names (e.g., ["precentral", "postcentral"]) and they are unioned before analysis. Output directories and file names use a +-joined convention (e.g., precentral+postcentral/).
  • Anisotropy Support in Flex-Search: The flex-search optimizer now supports all 4 SimNIBS conductivity models: isotropic (scalar), volume-normalized (vn), direct (dir), and multi-conductivity (mc). A dropdown in the GUI and FlexConfig.anisotropy_type parameter in the API control this.
  • Anisotropy Tuning Parameters: New aniso_maxratio and aniso_maxcond parameters on simulation and optimization configs let you control eigenvalue clamping for anisotropic simulations (defaults match SimNIBS: 10.0 and 2.0 S/m respectively).
  • Optimization Output Manifest: Every flex-search run now writes a flex_meta.json manifest alongside its results, recording the full configuration, best result, multi-start history, and a human-readable label. The simulator reads this manifest directly instead of parsing folder names.
  • Comprehensive Test Suite: 545 pytest tests running in 0.55 seconds, covering all core modules. Key coverage: calc 100%, paths 98%, sim/TI 87%, sim/mTI 90%, analyzer 82%, stats/config 95%, pre/structural 99%, opt/config 99%.
  • JSON Config Entry Points: All modules support simnibs_python -m tit.<module> config.json for programmatic and GUI-driven invocation. New tit/config_io.py handles typed serialization with _type discriminators.

Refactors & Improvements

  • Logger Simplification: Removed ~750 lines of custom handler/wrapper code. Two functions: setup_logging() and add_file_handler(). File-only logging with Qt bridge for GUI. Debug-mode checkboxes removed from all GUI tabs.
  • Module Reorganization: Dissolved tit/core/ – modules moved to tit/paths, tit/constants, tit/calc. NIfTI utilities moved to tit/stats/nifti. Mesh utilities moved to tit/tools/gmsh_opt.
  • Unified Analyzer: Single Analyzer class replaces the old MeshAnalyzer/VoxelAnalyzer split. Sphere and cortex ROI handling are unified. New run_group_analysis() function for multi-subject comparisons.
  • Simplified Python API: All modules now support clean one-liner imports:
    • from tit.sim import SimulationConfig, Montage, MontageMode, run_simulation
    • from tit.opt import FlexConfig, run_flex_search
    • from tit.opt import ExConfig, run_ex_search
    • from tit.analyzer import Analyzer, run_group_analysis
    • from tit.stats import run_group_comparison, GroupComparisonConfig
  • Flat Simulation Config: The simulation API was simplified from 5+ wrapper classes to 2 dataclasses. LabelMontage/XYZMontage replaced by a single Montage class with a MontageMode enum. ElectrodeConfig, IntensityConfig, and ConductivityType fields inlined directly into SimulationConfig.
  • Flat Optimization Configs: Flex-search ROI types, enums, and electrode config are now nested inside FlexConfig (e.g., FlexConfig.SphericalROI, FlexConfig.OptGoal). Ex-search current parameters inlined into ExConfig. Electrode classes accessed as ExConfig.PoolElectrodes and ExConfig.BucketElectrodes.
  • PathManager Rewrite: Replaced 930-line template engine with 180-line direct-method API (pm.m2m(sid), pm.simulation(sid, sim)). IDE autocompletion now works; typos caught at import time.
  • GUI Threading: Eliminated all blocking .wait() calls. Signal-based completion. Consistent subprocess pattern (config -> JSON -> subprocess) across all tabs.
  • Statistics Engine Refactor: Introduced PermutationEngine class that absorbs all control parameters, cutting internal function signatures from 16-17 arguments to 5-7. Dead code removed from I/O utilities. Public API (run_group_comparison, run_correlation) unchanged.
  • Blender Module Modernization: Typed config dataclasses (MontagePublicationConfig, VectorFieldConfig, RegionExportConfig), consolidated I/O utilities, __main__.py entry point, and deduplicated STL/PLY code.
  • Codebase Modernization: 657 type hint replacements across 55 files (modern list[X], X | None syntax). 27 dead constants removed. 16 overly broad exception handlers tightened. GUI color constants centralized in style.py.
  • CI/CD Improvements: Fixed Codecov upload in CircleCI. Added GitHub Actions workflow for MkDocs auto-deployment. Docker layer caching enabled. Codecov CLI cached between runs.
  • Reusable GUI Components: Extracted ROIPickerWidget, ElectrodeConfigWidget, SolverParamsWidget for cross-tab reuse. Three identical floating window classes consolidated into one generic class.

Fixes

  • Python 3.9 syntax errors fixed (str | Path without from __future__ import annotations).
  • SimNIBS S.fname_tensor now set correctly (was S.dti_nii – silently ignored by SimNIBS).
  • SimNIBS S.map_to_MNI capitalized correctly (was S.map_to_mni – MNI mapping was silently broken).
  • Dead S.anisotropy_type assignment on SESSION object removed (was no-op; correctly set on TDCSLIST).

Breaking Changes

  • tit.core.* imports removed – use tit.paths, tit.constants, tit.calc directly.
  • PathManager.path("key") template API removed – use direct methods (e.g., pm.m2m(sid)).
  • list_subjects() renamed to list_simnibs_subjects(). list_all_subjects() removed entirely.
  • MeshAnalyzer and VoxelAnalyzer deleted – use unified Analyzer class.
  • run_analysis() removed – use Analyzer.run() or run_group_analysis().
  • LabelMontage and XYZMontage deleted – use Montage with MontageMode enum.
  • ElectrodeConfig, IntensityConfig, ConductivityType deleted – fields inlined into SimulationConfig.
  • IntensityConfig(pair1=, pair2=) constructor removed – use intensities=[1.0, 1.0] list.
  • Standalone SphericalROI, AtlasROI, SubcorticalROI removed from tit.opt – access via FlexConfig.SphericalROI, etc.
  • OptGoal, FieldPostproc, NonROIMethod enums removed from tit.opt – access via FlexConfig.OptGoal, etc.
  • ExCurrentConfig deleted – current parameters inlined into ExConfig.
  • BucketElectrodes and PoolElectrodes standalone imports removed – access via ExConfig.BucketElectrodes, etc.
  • config.eeg_net removed from ExConfig – replaced with config.run_name (defaults to datetime).
  • generate_current_ratios() return type changed – now returns list instead of (list, bool).
  • Ex-search output JSON changed – analysis_results.json replaced with run_config.json. n_elements column removed from CSV.
  • Logger functions get_logger(), build_logger(), build_opt_logger() deleted – use logging.getLogger(__name__).
  • BenchmarkLogger and OptimizationLogger wrapper classes deleted – use standard logging module.
  • Flex-search output folders now use datetime naming (e.g., 20260307_143022/) instead of encoded ROI names. The flex_meta.json manifest replaces folder-name parsing.
  • mesh_utils.py renamed to gmsh_opt.py in tit/tools/.

Desktop App (v2.3.0): macOS Intel · macOS Apple Silicon · Windows · Linux AppImage · Linux deb

Other:

For installation instructions, see the Installation Guide.

Getting Help

If you encounter issues with this release:

  1. Check the Installation Guide for setup instructions
  2. Review the Troubleshooting section
  3. Search existing issues
  4. Ask in GitHub Discussions