# Bempp **URL:** https://bempp.discourse.group/c/bempp/7.md?page=1 [Latest](https://bempp.discourse.group/latest.md) · [Categories](https://bempp.discourse.group/categories.md) **Page:** 2 --- ## [Function for spatial derivative of the potential field](https://bempp.discourse.group/t/function-for-spatial-derivative-of-the-potential-field/134)
**Author:** [@mospel](https://bempp.discourse.group/u/mospel)\ **Replies:** 1\ **Last updated:** [29 April 2022 12:39 UTC](https://bempp.discourse.group/t/function-for-spatial-derivative-of-the-potential-field/134 "2022-04-29T12:39:52Z")
Are there functions in BEMPP to calculate the spatial gradient of the potential in a grid function? --- ## [AttributeError: '\_ProductDiscreteOperator' object has no attribute 'is\_barycentric'](https://bempp.discourse.group/t/attributeerror-productdiscreteoperator-object-has-no-attribute-is-barycentric/130)
**Author:** [@Gustavo](https://bempp.discourse.group/u/Gustavo)\ **Replies:** 1\ **Last updated:** [28 March 2022 11:51 UTC](https://bempp.discourse.group/t/attributeerror-productdiscreteoperator-object-has-no-attribute-is-barycentric/130 "2022-03-28T11:51:46Z")
Hi, This I’m having this error message AttributeError: '\_ProductDiscreteOperator' object has no attribute 'is\_barycentric'on the following piece of code: identity = bempp.api.operators.boundary.sparse.identity(space, s… --- ## [Problems using NtD operator](https://bempp.discourse.group/t/problems-using-ntd-operator/128)
**Author:** [@Gustavo](https://bempp.discourse.group/u/Gustavo)\ **Replies:** 2\ **Last updated:** [25 March 2022 12:03 UTC](https://bempp.discourse.group/t/problems-using-ntd-operator/128 "2022-03-25T12:03:57Z")
Solved by pulling the latest docker image. Thanks Hi, I have the following line of code in my notebook: ntd = bempp.api.operators.boundary.helmholtz.osrc\_ntd(space, k) and it gives me the following error: Attribut… --- ## [Cylinders origin](https://bempp.discourse.group/t/cylinders-origin/122)
**Author:** [@bartek](https://bempp.discourse.group/u/bartek)\ **Replies:** 2\ **Last updated:** [9 March 2022 16:15 UTC](https://bempp.discourse.group/t/cylinders-origin/122 "2022-03-09T16:15:15Z")
Hello Everyone, BEM++ seems to be a great and powerfull tool, however I have some stupid problem with a cylinder shape, trying to find the solutions of the Masxwell’s exquation for a radio wave. The object: bempp.api.s… --- ## [How to access matrix entries of boundary operators](https://bempp.discourse.group/t/how-to-access-matrix-entries-of-boundary-operators/115)
**Author:** [@Fabian](https://bempp.discourse.group/u/Fabian)\ **Replies:** 2\ **Last updated:** [25 January 2022 12:02 UTC](https://bempp.discourse.group/t/how-to-access-matrix-entries-of-boundary-operators/115 "2022-01-25T12:02:50Z")
Hi everyone. I’m still new to bempp, so I hope someone of you could answer my question. During solving acoustic problems with bempp using the Burton-Miller method, I came across some major differences from the obtained … --- ## [Problems running BEMpp under Docker](https://bempp.discourse.group/t/problems-running-bempp-under-docker/107)
**Author:** [@DAWardle](https://bempp.discourse.group/u/DAWardle)\ **Replies:** 10\ **Last updated:** [29 November 2021 11:12 UTC](https://bempp.discourse.group/t/problems-running-bempp-under-docker/107 "2021-11-29T11:12:48Z")
Hi everyone. I pulled the Docker image of BEMpp yesterday on a computer at work using: docker pull bempp/cl-notebook:latest The pull seemed to complete OK without errors. I then was able to get a JupyterLab notebook … --- ## [H2Opus library integration into bempp](https://bempp.discourse.group/t/h2opus-library-integration-into-bempp/108)
**Author:** [@piman](https://bempp.discourse.group/u/piman)\ **Replies:** 0\ **Last updated:** [23 November 2021 09:09 UTC](https://bempp.discourse.group/t/h2opus-library-integration-into-bempp/108 "2021-11-23T09:09:45Z")
Hi, I have found H2Opus library, a performance-oriented library for hierarchical matrices. It can be run on GPU, multi GPU, computational cluster cluster etc. and looks very efficient. At the end of the article they wand… --- ## [Docker installation POCL error](https://bempp.discourse.group/t/docker-installation-pocl-error/103)
**Author:** [@AndrewG](https://bempp.discourse.group/u/AndrewG)\ **Replies:** 5\ **Last updated:** [22 November 2021 09:43 UTC](https://bempp.discourse.group/t/docker-installation-pocl-error/103 "2021-11-22T09:43:55Z")
Hi BEMPP team, I’m trying to use BEMPP-CL for the first time. I used the docker installation, and ran the laplace\_interior\_dirichlet.ipynb notebook. Error message is pasted below. Machine Linux Mint 20.2. If I understan… --- ## [The Minor Influence of Vector Length on the Final Results](https://bempp.discourse.group/t/the-minor-influence-of-vector-length-on-the-final-results/106)
**Author:** [@LCheng](https://bempp.discourse.group/u/LCheng)\ **Replies:** 2\ **Last updated:** [19 November 2021 11:53 UTC](https://bempp.discourse.group/t/the-minor-influence-of-vector-length-on-the-final-results/106 "2021-11-19T11:53:52Z")
Hi, Bempp team, I am testing the vectorization acceleration for Bempp using OpenCL on ARM v8 CPU. The vector length of ARM V8 is 4, but I found that the assembled matrix with the vectorization mismatches with the non-ve… --- ## [The definition mismatch of the double layer operator](https://bempp.discourse.group/t/the-definition-mismatch-of-the-double-layer-operator/96)
**Author:** [@LCheng](https://bempp.discourse.group/u/LCheng)\ **Replies:** 2\ **Last updated:** [16 September 2021 01:24 UTC](https://bempp.discourse.group/t/the-definition-mismatch-of-the-double-layer-operator/96 "2021-09-16T01:24:57Z")
Hello, I found that the definition of the double layer on the “Bempp book” Bempp book is not matched with the publication(E. V. Wout, P. Gelat, T. Betcke and S. Arridge, 138(5), JASA, 2015). I have checked the Bempp c… --- ## [Ways to approximate singular surface integral in BEMPP](https://bempp.discourse.group/t/ways-to-approximate-singular-surface-integral-in-bempp/91)
**Author:** [@Dr.Gardiner](https://bempp.discourse.group/u/Dr.Gardiner)\ **Replies:** 5\ **Last updated:** [14 July 2021 18:37 UTC](https://bempp.discourse.group/t/ways-to-approximate-singular-surface-integral-in-bempp/91 "2021-07-14T18:37:59Z")
Consider the following integral I(\\vec z) = \\int\_{\\partial\\Omega} \\frac{e^{0.1(x\_1+2x\_2+3x\_3)}}{|\\vec z-\\vec x|} \\,dL(x), \\hspace{3mm}\\\\ \\vec x = (x\_1,x\_2,x\_3) \\in \\Omega, \\hspace{3mm} \\vec z = (z\_1,z\_2,z\_3) \\in \\par… --- ## [The Cross-node Parallelism Issue](https://bempp.discourse.group/t/the-cross-node-parallelism-issue/86)
**Author:** [@LCheng](https://bempp.discourse.group/u/LCheng)\ **Replies:** 3\ **Last updated:** [21 June 2021 08:42 UTC](https://bempp.discourse.group/t/the-cross-node-parallelism-issue/86 "2021-06-21T08:42:26Z")
Hi, dear bempp team, I am very appreciated about this excellent code and the platform which we can communicate with each other about BEM. I am planning to verify the capability of Bempp in simulating large-scale acousti… --- ## [Interface to kernel-independent FMM-like assembler](https://bempp.discourse.group/t/interface-to-kernel-independent-fmm-like-assembler/67)
**Author:** [@piman](https://bempp.discourse.group/u/piman)\ **Replies:** 3\ **Last updated:** [28 May 2021 11:28 UTC](https://bempp.discourse.group/t/interface-to-kernel-independent-fmm-like-assembler/67 "2021-05-28T11:28:55Z")
Dear bempp-cl team, I’m thinking of using a kernel-independent FFM-like assembler to speed up EM simulation, such as \[h2tools\] (Bitbucket). To apply it, I need a function that calculates a submatrix of matrix A based on… --- ## [Convective Wave Equation](https://bempp.discourse.group/t/convective-wave-equation/81)
**Author:** [@LCheng](https://bempp.discourse.group/u/LCheng)\ **Replies:** 2\ **Last updated:** [24 May 2021 02:44 UTC](https://bempp.discourse.group/t/convective-wave-equation/81 "2021-05-24T02:44:30Z")
Hi, do you think it is easy to extend the present bempp to consider the convective flow effect? It means that the convective wave equation in the frequency domain needs to be solved. It will be much more meaningful for a… --- ## [Problems running BEMPP on Mac](https://bempp.discourse.group/t/problems-running-bempp-on-mac/66)
**Author:** [@SebastianK](https://bempp.discourse.group/u/SebastianK)\ **Replies:** 3\ **Last updated:** [23 May 2021 18:31 UTC](https://bempp.discourse.group/t/problems-running-bempp-on-mac/66 "2021-05-23T18:31:10Z")
I am following the installation steps to install bempp 0.2.2 from source on my mac (Catalina 10.15.7). After installation I am getting the following error running sphere scattering example: from bempp.api.linalg import… --- ## [Is it worth using gpu on boundary operators?](https://bempp.discourse.group/t/is-it-worth-using-gpu-on-boundary-operators/76)
**Author:** [@Varoloc](https://bempp.discourse.group/u/Varoloc)\ **Replies:** 0\ **Last updated:** [21 April 2021 16:36 UTC](https://bempp.discourse.group/t/is-it-worth-using-gpu-on-boundary-operators/76 "2021-04-21T16:36:26Z")
I was checking out the Bempp OpenCL performance benchmarks and it got me thinking why bemp.api.POTENTIAL\_OPERATOR\_DEVICE\_TYPE = ‘gpu’ was tested but no bemp.api.BOUNDARY\_OPERATOR\_DEVICE\_TYPE = ‘gpu’ was included in the… --- ## [System Deflation](https://bempp.discourse.group/t/system-deflation/74)
**Author:** [@Peter](https://bempp.discourse.group/u/Peter)\ **Replies:** 1\ **Last updated:** [16 April 2021 10:42 UTC](https://bempp.discourse.group/t/system-deflation/74 "2021-04-16T10:42:24Z")
Dear bempp-cl team, When solving a problem for the electric potential I have a system that is in principle singular. My system is (0.5M+DLP)\\phi = F, where M is the identity operator (or mass matrix), DLP is the double… --- ## [Exporting Calculated Solution as Arrays of Indices](https://bempp.discourse.group/t/exporting-calculated-solution-as-arrays-of-indices/64)
**Author:** [@gwang4](https://bempp.discourse.group/u/gwang4)\ **Replies:** 1\ **Last updated:** [12 February 2021 10:07 UTC](https://bempp.discourse.group/t/exporting-calculated-solution-as-arrays-of-indices/64 "2021-02-12T10:07:35Z")
Hello, I have calculated a solution for Laplace’s equation (for electric field) using Dirichlet boundary conditions, and am able to generate a Trisurf Plot of the solution within Jupyter. Is there a way to export this d… --- ## [Grid function coefficients](https://bempp.discourse.group/t/grid-function-coefficients/49)
**Author:** [@Peter](https://bempp.discourse.group/u/Peter)\ **Replies:** 3\ **Last updated:** [1 February 2021 11:01 UTC](https://bempp.discourse.group/t/grid-function-coefficients/49 "2021-02-01T11:01:44Z")
Hi all, For my project I am interested in improving the accuracy of my solution with higher order functions, therefore I am restricted to using the legacy version of bempp. My question is about coefficients, both in th… --- ## [Slow Maxwell FMM](https://bempp.discourse.group/t/slow-maxwell-fmm/56)
**Author:** [@mandyxmq](https://bempp.discourse.group/u/mandyxmq)\ **Replies:** 1\ **Last updated:** [27 January 2021 00:59 UTC](https://bempp.discourse.group/t/slow-maxwell-fmm/56 "2021-01-27T00:59:18Z")
I’m using bempp-cl 0.2.2 and trying to use FMM for Electromagnetic scattering problems. I created a test based on the maxwell\_dielectric tutorial example (I changed two spheres to one and changed some parameters). I obse… --- ## [At which grid size does FMM become 'worth it'?](https://bempp.discourse.group/t/at-which-grid-size-does-fmm-become-worth-it/50)
**Author:** [@Rasmus](https://bempp.discourse.group/u/Rasmus)\ **Replies:** 4\ **Last updated:** [7 January 2021 13:41 UTC](https://bempp.discourse.group/t/at-which-grid-size-does-fmm-become-worth-it/50 "2021-01-07T13:41:15Z")
Hi everyone. Thanks a lot for all the help so far. I’m (still) doing Helmholtz scattering on a rigid object. I’m using somewhat large grid’s, and my simulations takes a long time to compute. import time import bempp.ap… --- ## [The ACA or other algorithm to accelerate bempp?](https://bempp.discourse.group/t/the-aca-or-other-algorithm-to-accelerate-bempp/42)
**Author:** [@hellojxt](https://bempp.discourse.group/u/hellojxt)\ **Replies:** 1\ **Last updated:** [29 October 2020 16:57 UTC](https://bempp.discourse.group/t/the-aca-or-other-algorithm-to-accelerate-bempp/42 "2020-10-29T16:57:28Z")
Hi, Does bempp support The Adaptive Cross Approximation Algorithm? I can’t find the relevant description in the document. But I saw the relevant introduction in an article citing bempp: When I select the assember as … --- ## [Boundary layer effect](https://bempp.discourse.group/t/boundary-layer-effect/35)
**Author:** [@Sangwoo.Kang](https://bempp.discourse.group/u/Sangwoo.Kang)\ **Replies:** 2\ **Last updated:** [12 October 2020 11:04 UTC](https://bempp.discourse.group/t/boundary-layer-effect/35 "2020-10-12T11:04:16Z")
Hello Thanks to your great project, I’m applying bempp to my project (related to Maxwell equations). Now, the final step only remains that is to calculate the electric field inside of the target with the potential oper… --- ## [FMM Memory Usage Statistics](https://bempp.discourse.group/t/fmm-memory-usage-statistics/32)
**Author:** [@DerekOlson](https://bempp.discourse.group/u/DerekOlson)\ **Replies:** 2\ **Last updated:** [11 October 2020 17:52 UTC](https://bempp.discourse.group/t/fmm-memory-usage-statistics/32 "2020-10-11T17:52:00Z")
Dear bempp-cl team, I would like to be able to track the memory usage (compression) for FMM assembly. In the older version of Bempp, the console logger reported both time per iteration, and memory compression for the H-… --- ## [Masters project ideas](https://bempp.discourse.group/t/masters-project-ideas/30)
**Author:** [@djanekovic](https://bempp.discourse.group/u/djanekovic)\ **Replies:** 1\ **Last updated:** [2 October 2020 16:58 UTC](https://bempp.discourse.group/t/masters-project-ideas/30 "2020-10-02T16:58:21Z")
Hi all, I just posted on github but maybe it makes sense to post similar question here too. I am currently masters student looking for the project for my masters thesis. I am enrolled in CS/Computer Engineering and I am … [Previous page](https://bempp.discourse.group/c/bempp/7.md)