# Latest **URL:** https://simpeg.discourse.group/latest.md [Latest](https://simpeg.discourse.group/latest.md) · [Categories](https://simpeg.discourse.group/categories.md) --- ## [Welcome to the SimPEG Discourse](https://simpeg.discourse.group/t/welcome-to-the-simpeg-discourse/7)
**Author:** [@lheagy](https://simpeg.discourse.group/u/lheagy)\ **Replies:** 0\ **Last updated:** [November 8, 2019, 4:45am UTC](https://simpeg.discourse.group/t/welcome-to-the-simpeg-discourse/7 "2019-11-08T04:45:12Z")
Welcome to the SimPEG discourse! This is a place for the SimPEG community to interact with one another, ask questions, share ideas, find collaborators, ask for help, and provide support to other community members. Who i… --- ## [TensorMesh.write\_vtk](https://simpeg.discourse.group/t/tensormesh-write-vtk/806)
**Author:** [@Olaf\_Arroyo](https://simpeg.discourse.group/u/Olaf_Arroyo)\ **Replies:** 1\ **Last updated:** [August 18, 2026, 7:16pm UTC](https://simpeg.discourse.group/t/tensormesh-write-vtk/806 "2026-08-18T19:16:11Z")
Hello! I´m running the first part of the example “3D Inversion of Gravity Anomaly Data”, exactly until the plot of the inversion using a tensor mesh. I try to create a vtk file, for visualization in Paraview, so I add … --- ## [Posterior uncertainty on a published gravity inversion: the gates, a retraction, and what I got wrong](https://simpeg.discourse.group/t/posterior-uncertainty-on-a-published-gravity-inversion-the-gates-a-retraction-and-what-i-got-wrong/807)
**Author:** [@vaishak-vn](https://simpeg.discourse.group/u/vaishak-vn)\ **Replies:** 0\ **Last updated:** [August 2, 2026, 7:25am UTC](https://simpeg.discourse.group/t/posterior-uncertainty-on-a-published-gravity-inversion-the-gates-a-retraction-and-what-i-got-wrong/807 "2026-08-02T07:25:42Z")
Hi all. I’m Vaishak, coming from software and ML rather than geophysics, so please read this with that in mind. Over the last few months I reproduced a published potential-field inversion and computed the posterior unce… --- ## [Inversion of magnetization amplitude with different direction than external field](https://simpeg.discourse.group/t/inversion-of-magnetization-amplitude-with-different-direction-than-external-field/737)
**Author:** [@clairebouligand](https://simpeg.discourse.group/u/clairebouligand)\ **Replies:** 4\ **Last updated:** [March 26, 2026, 7:06pm UTC](https://simpeg.discourse.group/t/inversion-of-magnetization-amplitude-with-different-direction-than-external-field/737 "2026-03-26T19:06:21Z")
Hi, I would like to know if this is possible to do an inversion of magnetization or pseudo-susceptibility assuming the magnetization direction is different from the external field. I have tested the mvi inversion by imp… --- ## [Error from multiple receivers per source dipole](https://simpeg.discourse.group/t/error-from-multiple-receivers-per-source-dipole/793)
**Author:** [@UTMZ17N](https://simpeg.discourse.group/u/UTMZ17N)\ **Replies:** 4\ **Last updated:** [March 10, 2026, 10:07pm UTC](https://simpeg.discourse.group/t/error-from-multiple-receivers-per-source-dipole/793 "2026-03-10T22:07:22Z")
Okay, so.. I’m using the read\_dcip\_xyz() function for a 3D DCIP inversion and run into issues with the number of sources vs receivers generated. The actual survey was completed using a Pole-Dipole array, where the B el… --- ## [Stretched-exponential TDIP inversion](https://simpeg.discourse.group/t/stretched-exponential-tdip-inversion/792)
**Author:** [@a.benavides](https://simpeg.discourse.group/u/a.benavides)\ **Replies:** 0\ **Last updated:** [February 18, 2026, 5:18pm UTC](https://simpeg.discourse.group/t/stretched-exponential-tdip-inversion/792 "2026-02-18T17:18:04Z")
Hi, I am working on developing a spectral IP (SIP) method to run on SimPEG. I learn that SimPEG can perform stretched-exponential inversion (SEI). There is very little information online about this feature and the closes… --- ## [Discrepencies in Apparent Resistivity on a Uniform Half-Space](https://simpeg.discourse.group/t/discrepencies-in-apparent-resistivity-on-a-uniform-half-space/758)
**Author:** [@kianadmvnd](https://simpeg.discourse.group/u/kianadmvnd)\ **Replies:** 0\ **Last updated:** [February 5, 2026, 5:24pm UTC](https://simpeg.discourse.group/t/discrepencies-in-apparent-resistivity-on-a-uniform-half-space/758 "2026-02-05T17:24:24Z")
Hi all, I am trying to perform a DC resistivity forward simulation on a uniform half-space with a resistivity of 5000 Ohm.m. I am using a dipole-dipole survey (a=1, n=16). In my results, the calculated apparent resisti… --- ## [Asymmetry in apparent chargeability pseudosection](https://simpeg.discourse.group/t/asymmetry-in-apparent-chargeability-pseudosection/743)
**Author:** [@kianadmvnd](https://simpeg.discourse.group/u/kianadmvnd)\ **Replies:** 3\ **Last updated:** [January 28, 2026, 10:44pm UTC](https://simpeg.discourse.group/t/asymmetry-in-apparent-chargeability-pseudosection/743 "2026-01-28T22:44:12Z")
Hi everyone, I’m seeing a small asymmetry in apparent chargeability values, even though both the model and acquisition geometry are symmetric. For the same setup, Res2Dmod gives perfectly symmetric results. Example for… --- ## [Relevant contents of seismic refraction forward and inversion](https://simpeg.discourse.group/t/relevant-contents-of-seismic-refraction-forward-and-inversion/367)
**Author:** [@Hui](https://simpeg.discourse.group/u/Hui)\ **Replies:** 8\ **Last updated:** [December 10, 2025, 2:39pm UTC](https://simpeg.discourse.group/t/relevant-contents-of-seismic-refraction-forward-and-inversion/367 "2025-12-10T14:39:42Z")
Hello, I’m a university student majoring in geophysics. I want to ask you a question: Is there any code related to seismic refraction forward and inversion in simpeg? I would be very happy if you could spare me precious … --- ## [How to optimize inversion results](https://simpeg.discourse.group/t/how-to-optimize-inversion-results/739)
**Author:** [@lazyn](https://simpeg.discourse.group/u/lazyn)\ **Replies:** 0\ **Last updated:** [November 26, 2025, 9:27am UTC](https://simpeg.discourse.group/t/how-to-optimize-inversion-results/739 "2025-11-26T09:27:39Z")
Hello, I modified the official example code plot\_inv\_2\_dcip2d.py and used my own data to invert for resistivity and chargeability. The inversion results are not good, showing large areas of very high values. I tried adj… --- ## [Running PGI demo in PyCharm](https://simpeg.discourse.group/t/running-pgi-demo-in-pycharm/738)
**Author:** [@MarcV](https://simpeg.discourse.group/u/MarcV)\ **Replies:** 1\ **Last updated:** [November 22, 2025, 12:37am UTC](https://simpeg.discourse.group/t/running-pgi-demo-in-pycharm/738 "2025-11-22T00:37:09Z")
I get the following error when I run the plot\_inv\_0\_PGI\_Linear\_1D.py example on PyCharm, I run into the following error: C:\\Users\\Marc\\Documents\\Logiciels\\Alphatrim\\SimPEG\_0.24\\Scripts\\python.exe C:\\Users\\Marc\\Documents… --- ## [TreeMesh.write\_vtk](https://simpeg.discourse.group/t/treemesh-write-vtk/736)
**Author:** [@dsherman42](https://simpeg.discourse.group/u/dsherman42)\ **Replies:** 1\ **Last updated:** [October 8, 2025, 8:12pm UTC](https://simpeg.discourse.group/t/treemesh-write-vtk/736 "2025-10-08T20:12:22Z")
Hi all, I have tried using the TreeMesh.write\_vtk method to output the final models of my 3d mag inversion to vtk format, but an error tells me that write\_vtk is not associated with my mesh. Is this no longer a supporte… --- ## [Empymod compare to Dipole1d](https://simpeg.discourse.group/t/empymod-compare-to-dipole1d/724)
**Author:** [@mhovers](https://simpeg.discourse.group/u/mhovers)\ **Replies:** 0\ **Last updated:** [June 26, 2025, 9:59pm UTC](https://simpeg.discourse.group/t/empymod-compare-to-dipole1d/724 "2025-06-26T21:59:46Z")
I am trying to compare empymod to Kerry Key’s Dipole1d and having mismatches that I am sure are due to my misuse of empymod. Is there a way I can upload an exampe Jupyter notebook with the example? thanks Mike Hoverste… --- ## [Cross-Gradient Joint Inversion](https://simpeg.discourse.group/t/cross-gradient-joint-inversion/723)
**Author:** [@33geo](https://simpeg.discourse.group/u/33geo)\ **Replies:** 0\ **Last updated:** [June 11, 2025, 12:59pm UTC](https://simpeg.discourse.group/t/cross-gradient-joint-inversion/723 "2025-06-11T12:59:01Z")
Dear all, I am currently using the SimPEG library, which I consider to be an exceptionally robust and versatile computational tool. At present, I am performing a joint inversion of gravity and magnetic data using the cr… --- ## [Optimization on 3D DC inversion](https://simpeg.discourse.group/t/optimization-on-3d-dc-inversion/722)
**Author:** [@fabioca](https://simpeg.discourse.group/u/fabioca)\ **Replies:** 1\ **Last updated:** [June 5, 2025, 6:18pm UTC](https://simpeg.discourse.group/t/optimization-on-3d-dc-inversion/722 "2025-06-05T18:18:57Z")
Hello, I am using SimPEG to invert 16 dipole-dipole profiles for 3D structure. I basically work on the tutorial script: 3D Least-Squares Inversion of DC Resistivity Data — SimPEG 0.24.0 documentation My problem is that … --- ## [Can I do 2D MT inversion using SimPEG?](https://simpeg.discourse.group/t/can-i-do-2d-mt-inversion-using-simpeg/709)
**Author:** [@liyd02](https://simpeg.discourse.group/u/liyd02)\ **Replies:** 0\ **Last updated:** [April 23, 2025, 9:00am UTC](https://simpeg.discourse.group/t/can-i-do-2d-mt-inversion-using-simpeg/709 "2025-04-23T09:00:21Z")
I want to perform 2D inversion of MT data. However, I cannot find examples under the directory nsem. I’d like to know can SimPEG perform 2D inversion of MT data? If this is the case, how can I do it? Thank you very much. … --- ## [SimPEG v0.23.0 Magnetic Susceptibility Inversion Error - TypeError: Object must be an instance of Data](https://simpeg.discourse.group/t/simpeg-v0-23-0-magnetic-susceptibility-inversion-error-typeerror-object-must-be-an-instance-of-data/706)
**Author:** [@kk333](https://simpeg.discourse.group/u/kk333)\ **Replies:** 0\ **Last updated:** [April 13, 2025, 6:46am UTC](https://simpeg.discourse.group/t/simpeg-v0-23-0-magnetic-susceptibility-inversion-error-typeerror-object-must-be-an-instance-of-data/706 "2025-04-13T06:46:38Z")
Hello SimPEG community, I’m working on a magnetic data processing and susceptibility inversion application. After successfully implementing the data processing part (gridding, RTP, upward continuation), I’m encountering… --- ## [Zero active cell](https://simpeg.discourse.group/t/zero-active-cell/696)
**Author:** [@Shruti](https://simpeg.discourse.group/u/Shruti)\ **Replies:** 0\ **Last updated:** [April 4, 2025, 1:25pm UTC](https://simpeg.discourse.group/t/zero-active-cell/696 "2025-04-04T13:25:48Z")
i have my easting northing as receiver location along with elevation. But when i use it for making a tensor mesh the code says no active cell found. what could be possible problem? Can someone explain me the workflow and… --- ## [Can I use IRLS (e.g., Lp-norm) regularization on the gravity and magnetic models while still using cross-gradient as a coupling term?](https://simpeg.discourse.group/t/can-i-use-irls-e-g-lp-norm-regularization-on-the-gravity-and-magnetic-models-while-still-using-cross-gradient-as-a-coupling-term/694)
**Author:** [@Mr.Xingfeng](https://simpeg.discourse.group/u/Mr.Xingfeng)\ **Replies:** 0\ **Last updated:** [April 3, 2025, 1:31pm UTC](https://simpeg.discourse.group/t/can-i-use-irls-e-g-lp-norm-regularization-on-the-gravity-and-magnetic-models-while-still-using-cross-gradient-as-a-coupling-term/694 "2025-04-03T13:31:59Z")
I’m working on a joint inversion of gravity and magnetic data in SimPEG, and I want to incorporate cross-gradient coupling between the two models. I know that SimPEG supports IRLS for sparsity-promoting regularization … --- ## [Understanding of the mathematical framework](https://simpeg.discourse.group/t/understanding-of-the-mathematical-framework/639)
**Author:** [@33geo](https://simpeg.discourse.group/u/33geo)\ **Replies:** 1\ **Last updated:** [March 26, 2025, 2:40am UTC](https://simpeg.discourse.group/t/understanding-of-the-mathematical-framework/639 "2025-03-26T02:40:18Z")
Congratulations! SimPEG is truly an incredible tool! I recently started using it and would like to deepen my understanding of the mathematical framework underlying the forward modeling and inverse problem. Could you kind… --- ## [Gravity inversion for four bodies](https://simpeg.discourse.group/t/gravity-inversion-for-four-bodies/682)
**Author:** [@Anish](https://simpeg.discourse.group/u/Anish)\ **Replies:** 0\ **Last updated:** [March 25, 2025, 8:01am UTC](https://simpeg.discourse.group/t/gravity-inversion-for-four-bodies/682 "2025-03-25T08:01:49Z")
Hi everyone, I have a question regarding the gravity inversion, as in the tutorial it is used with two bodies, one block, and one sphere, but I am using the four bodies with two spheres and two blocks. I performed the f… --- ## [Possible bug in BaseRx.eval() when using resistivity](https://simpeg.discourse.group/t/possible-bug-in-baserx-eval-when-using-resistivity/571)
**Author:** [@Roland](https://simpeg.discourse.group/u/Roland)\ **Replies:** 4\ **Last updated:** [February 22, 2025, 7:50pm UTC](https://simpeg.discourse.group/t/possible-bug-in-baserx-eval-when-using-resistivity/571 "2025-02-22T19:50:51Z")
Hi, Using SimPEG 0.21.1 on Ubuntu. I’m trying to write a 3D resistivity inversion script, basing my code off the various tutorials. When I run it, it starts the actual inversion then stops with an error message as belo… --- ## [1D FDEM reciever location problem](https://simpeg.discourse.group/t/1d-fdem-reciever-location-problem/662)
**Author:** [@izoud](https://simpeg.discourse.group/u/izoud)\ **Replies:** 0\ **Last updated:** [February 18, 2025, 12:39pm UTC](https://simpeg.discourse.group/t/1d-fdem-reciever-location-problem/662 "2025-02-18T12:39:05Z")
Hello, I’m new to simpeg, maybe someone can give me an advice on following topic: I want to use it for 1D FDEM Forward Simulation. The assumption is that the source is on the ground and the receiver is in the air. I set… --- ## [1D RESOLVE Bookpurnong Inversion](https://simpeg.discourse.group/t/1d-resolve-bookpurnong-inversion/136)
**Author:** [@wouterdls](https://simpeg.discourse.group/u/wouterdls)\ **Replies:** 2\ **Last updated:** [January 7, 2025, 8:16pm UTC](https://simpeg.discourse.group/t/1d-resolve-bookpurnong-inversion/136 "2025-01-07T20:16:57Z")
Hi everyone! I’m exploring SimPEG with the 1D RESOLVE Bookpurnong Inversion jupyter notebook. It’s nice, because it is related to my research. However, I cannot reproduce the inversion from the paper. I changed the not… --- ## [Modelling x component in TDEM tutorials](https://simpeg.discourse.group/t/modelling-x-component-in-tdem-tutorials/647)
**Author:** [@Kellett](https://simpeg.discourse.group/u/Kellett)\ **Replies:** 0\ **Last updated:** [December 29, 2024, 9:59pm UTC](https://simpeg.discourse.group/t/modelling-x-component-in-tdem-tutorials/647 "2024-12-29T21:59:55Z")
Hello, I have been looking at the X component in some SkyTEM data collected recently as part of a survey over a landslide in NZ. I was interested in testing some modelling approaches using the SimPEG TDEM tutorials(eg fw… --- ## [Joint inversion for grav and mag](https://simpeg.discourse.group/t/joint-inversion-for-grav-and-mag/645)
**Author:** [@GoatSuey](https://simpeg.discourse.group/u/GoatSuey)\ **Replies:** 0\ **Last updated:** [December 19, 2024, 3:53pm UTC](https://simpeg.discourse.group/t/joint-inversion-for-grav-and-mag/645 "2024-12-19T15:53:59Z")
Hi all, I have been using SimPEG cross gradient inversion code for gravity and magnetics for a while and although it works fine I want to ask: Is it possible to add borehole data and e.g. a density model as prior infor… --- ## [Waveform definition](https://simpeg.discourse.group/t/waveform-definition/641)
**Author:** [@glow](https://simpeg.discourse.group/u/glow)\ **Replies:** 0\ **Last updated:** [December 4, 2024, 10:38am UTC](https://simpeg.discourse.group/t/waveform-definition/641 "2024-12-04T10:38:42Z")
Regarding the emission waveform of this transient electromagnetic, how should I redefine it in Simpeg’s waveform definition? Here are some measured parameters, Frequency: 240.0 TIME\_DELAY: -1.7E-6 RAMP\_TIME: 4E-6 RAM… --- ## [Gravity: is it possible to do the simulation for 2D model by setting y axis as a single value?](https://simpeg.discourse.group/t/gravity-is-it-possible-to-do-the-simulation-for-2d-model-by-setting-y-axis-as-a-single-value/255)
**Author:** [@Astor](https://simpeg.discourse.group/u/Astor)\ **Replies:** 4\ **Last updated:** [November 26, 2024, 4:11am UTC](https://simpeg.discourse.group/t/gravity-is-it-possible-to-do-the-simulation-for-2d-model-by-setting-y-axis-as-a-single-value/255 "2024-11-26T04:11:58Z")
Hi, I saw there are forward and inversion examples for gravity based on a 3D model. I need to do some verification on a 2D model. So I would like to know how can I do the simulation based on a 2D model. Is it possible b… --- ## [Can SimPEG use GPU?](https://simpeg.discourse.group/t/can-simpeg-use-gpu/632)
**Author:** [@anagmantilla](https://simpeg.discourse.group/u/anagmantilla)\ **Replies:** 1\ **Last updated:** [November 25, 2024, 7:35pm UTC](https://simpeg.discourse.group/t/can-simpeg-use-gpu/632 "2024-11-25T19:35:02Z")
Hi, I would like to know if there is a way to use GPU with SimPEG. Especially doing 3D inversions, which usually take a lot of time. Thanks --- ## [3D TDEM Forward Problem about how to extract the fields value](https://simpeg.discourse.group/t/3d-tdem-forward-problem-about-how-to-extract-the-fields-value/630)
**Author:** [@glow](https://simpeg.discourse.group/u/glow)\ **Replies:** 1\ **Last updated:** [November 20, 2024, 9:27am UTC](https://simpeg.discourse.group/t/3d-tdem-forward-problem-about-how-to-extract-the-fields-value/630 "2024-11-20T09:27:23Z")
I want to extract the electric field values on each grid obtained through the direct solver during the TDEM calculation process, and then calculate the final electromagnetic response. However, due to the large matrix of … [Next page](https://simpeg.discourse.group/latest.md?page=1)