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FDTD, Low-Frequency, Neuron, Mode-Matching, Flow, Acoustics, etc...

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  • FDTD, Low-Frequency, Neuron, Mode-Matching, Flow, Acoustics, etc...

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    N
    Hi! Can someone help me understand if it makes sense to calculate SAR statistics in a low frequency electrical stimulation (30 Hz)? Thanks!!
  • Simulations fail when multiple simulations are submitted

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    By default, Sim4Life tries to use all available resources to start as many simulations as you submit or have cores or GPUs available. The first simulation usually starts fine, and the rest fail due to insufficient licenses. You have the option to limit the number of simultaneous simulations in the ARES tool. Please change the Resource Management Option from Concurrent Jobs to One Job at a time as in the attached screenshot. [image: 1569997460703-ares3.jpg]
  • what's the difference between red lines and white lines in gridding?

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    S
    Thank you for the great explanation.
  • Jobs suddenly remain queued indefinitely

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    P
    After a call with S4L support, here is the solution for future reference: My machine had two GPUs connected, one of them old and deactivated. However, the script ExtractCudaInfo.py detected both of these in the line 'num_gpus = int(xml_root.find("attached_gpus").text)' and then got stuck trying to find information on the deactivated GPU. A quick fix for the issue is therefore to manually set the correct number, in my case 'num_gpus=1', in the script.
  • High Field Values at Extremities

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    Hi @bryn, I think you’re right. The issue appears to be related to the boundary conditions on the outer bounding box. I changed the boundary to a flux(0) condition, and that resolved the problem with the localized high field values at the extremities. Thank you!
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  • "wire radius"

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    brynB
    Please give more context. E.g., "in the modeler when I use tool X", or in a "Y simulation" there is an option. or in this other thread (link) I asked about Z Then it will be easier to answer your question.
  • Yoon-sun Arm Stimulation Neuron Tutorial Project Compatibility Issue

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    Are you able to run other NEURON tutorials (the pre-build versions)? If not then this issue could be related to the NEURON installation or version. It is possible that using an older version of the NEURON solver is causing the error you mentioned. Please make sure you have the correct version of NEURON installed in your Sim4Life folder. For instance, as you are using Sim4Life version 8.2.0.16876, you should download NEURON using NEURON_setup_8.2.0.16876.exe.
  • Modulated source in thermal simulation

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    @Sylvain Hi, thank you for your reply. I changed modulated field to El. Loss Density and everything works.
  • Thermal, unable to write input files.

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    Thank you. Uploaded.
  • MQS solver errors

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    sending you an email via support
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  • This topic is deleted!

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  • How to get inhomogeneous B0 maps

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  • Simulation outputs

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    Great! Goit it, thank you so much. One last question regarding where the simulation outputs are located and saved. The coordinates of the voxelized entities where can be found? Thank you so much for your time :)
  • White matter anisotropy

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    @bryn Thanks, I found it!
  • Unable to start simulation: failed to write input files.

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    ofliO
    Hi @tayjiekai sim4life.lite is the student version of our online simulation platform sim4life.science and comes with certain limitations. As indicated by the error message, it does not support a number of neurons exceeding 10. If the limitations of sim4life.lite are too restrictive for your work, I suggest transitioning to the full Sim4Life web version at sim4life.science.
  • EM FTDM simulation

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    Joule heating sources from various processes (e.g., EM energy deposition by ohmic losses) can be considered as inhomogeneous heat sources in thermal simulations. To create heat sources Simulation Link: Sensor settings of an EM FDTD simulation in the same project can then be dragged and dropped into Source Settings folder. Modulated Analysis/Cache: Data Origin Type can be defined as: (a) Cache File: select the path of a thermal source previously exported into a .cache file. (b) Analysis Output: select the energy density of interest directly from the Analysis. You can look into the heated brain tutorial for a simplified example.
  • 'conductivity is not vanishing (conductivity cannot be considered)'

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    SylvainS
    Hi, There is most likely an error due to a sanity check, since you appear to have lossy tissues in your simulation and the Magneto Static Vector Potential solver does not account for those losses. Having a ferrous core, however, you do need to use that solver. The trick is to chain 2 simulations: one that solves the magnetic vector potential (A), and one that uses this A as a source term to determine the induced electric field (this time accounting for losses). The key is to remove the lossy tissues from the first simulation (only metallic or ferrous materials play a role anyhow). I would recommend you have a look at the LF tutorial called "Wireless Power Transfer: Exposure Assessment", since it uses the same technique. In addition, it seems that "The solver may have run out of RAM"... I would therefore check the RAM usage to make sure it's not going beyond your resources. Note that using the technique above allows you to have two different resolutions: one optimized to properly resolve the coil, the other to resolve the tissues (as long as the domain sizes of the first simulation is large enough to include that of the second). This usually leads to smaller grid sizes, thereby reducing the RAM usage...
  • Errors QS MPI

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    M
    Hi Andrei, I replied on the other thread: https://forum.zmt.swiss/post/1941
  • Errors QS MPI

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    M
    Hi Andrei, this error shows when there are not enough MPI-QS tokens on your license to use all cores on your computer. If parallelization is set to automatic, Sim4Life iSolve will try to use all available cores, and one MPI-QS token per core is needed. You can change the number of processes (=cores) to be used by setting parallelization to Manual and entering the number of MPI-QS tokens + 1 (solver license).