SAMG for groundwater simulation

Mesh-Agnostic yet fast

SAMG is a very efficient linear solver library based on algebraic multigrid (AMG) specifically developed for industrial applications. SAMG supports both serial and multi-core computations on single PCs, workstations or compute nodes.

LMG is an interface linking the SAMG library to MODFLOW. There are three versions of LMG: LMG-2kx supports MODFLOW-2000 and MODFLOW-2005, LMG-USG supports MODFLOW-USG and LMG-MF6 supports MODFLOW-6.

Key Features of SAMG:

  • State-of-the-art AMG performance – applicable for structured and unstructured meshes.
  • Optimized solver control including automated-setup-reuse and switching between different solvers.
  • Supports both multi-core and multi-node systems.

Advantages for MODFLOW:

  • „Big Models“: Allows increased modeling accuracy for both structured and unstructured models (as in MODFLOW-USG and MODFLOW-6), while keeping compute times manageable.
  • Handles strongly heterogeneous and unstructured models where standard solvers have problems. No additional knowledge about solvers needed.

The graph shows computing times for the MODFLOW 6 model test007_751x751 with roughly 600,000 grid-cells. While PCG is very sensitive to the relaxation factor used, LMG does not need additional parameters set by the user. LMG achieves a speed-up of 5.1 on a single core and a speed-up of 11.8 on 4 cores compared with PCG. Hence, the total runtime with LMG is reduced by a factor of 3.4 on a single core and a factor of 5.1 on 4 cores compared with the total runtime using PCG. The runtime of SAMG grows only linearly with the number of equations. For this reason, the speed-up of LMG compared to PCG will increase for bigger models.

User Comments

“...Without SAMG as our solver engine, it would have been impossible to solve [transport models with up to 30 million variables] in a practicable time.” – DHI-WASY GmbH

“[SAMG] was able to reduce the compute time of [one of] our simulations from 12 hours to 3 hours, so our engineers can now run multiple simulations a day.” – ITASCA DENVER Inc.

“In general, the SAMG solver is the fastest MODFLOW solver that [we] have used.” – Aquaveo LLC

“[SAMG] provided optimal runtime speed compared to public-domain solvers evaluated....” – GeoHydroScience LLC

“In general, the SAMG solver is the fastest MODFLOW solver that [we] have used. I have seen multiple models where the SAMG solver was not only faster but more stable than the standard MODFLOW solvers” – Aquaveo LLC

Commercial references

The following companies offer SAMG in their groundwater simulation software:

Aquaveo LLC
Environmental Simulations Inc.
HydroAlgorithmic Pty Ltd
ITASCA Denver Inc.
Waterloo Hydrogeologic


SAMG is now available for use with MODFLOW-6

Available licenses:

The SAMG-MODFLOW package includes:

  • SAMG-MODFLOW library (dll) * for Windows. Linux libraries are also available upon request.
  • MODFLOW-2005, MODFLOW-2000, MODFLOW-USG and MODFLOW-6 linked to the SAMG-MODFLOW Library
  • Documentation
  • Test Models
  • Interface description to link SAMG-MODFLOW to your own MODFLOW code.

License Type | Price

  • 30-day Evaluation License | free
  • Research License (node-locked) | 560,- €**
  • Research License (floating) | 850,- €**
  • Regular License (node-locked) | 790,- €**
  • Regular License (floating) | 1.180,- €**

* SAMG-MODFLOW uses SAMG but does not offer access to all functions included in the full SAMG library
** Prices excluding 19 % German VAT.
Multiple Licenses are available at reduced rates.


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Phone +49 2241 14-4400
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