# \#gridap

**URL:** https://discourse.julialang.org/tag/gridap/551.md

[Latest](https://discourse.julialang.org/latest.md) · [Categories](https://discourse.julialang.org/categories.md) · [Tags](https://discourse.julialang.org/tags.md)

---

## [Upwinding in Gridap](https://discourse.julialang.org/t/upwinding-in-gridap/127571)

<div class="topic-metadata">

**Author:** [@Simons](https://discourse.julialang.org/u/Simons)\
**Replies:** 1\
**Last updated:** [June 17, 2026, 1:48pm UTC](https://discourse.julialang.org/t/upwinding-in-gridap/127571 "2026-06-17T13:48:27Z")

</div>

Hi all, I want to solve an advection-diffusion problem with DG and upwinding. Specifically, I need to define the form f1(u,v) = ∫( upwinded(u, b, n\_Λ) \* v )dΛ where upwinded(u, b, n\_Λ) = u.plus if dot(b, n\_\\Lambda.p…

---

## [Gridap use for finite element modelling for electrochemical electrode modelling](https://discourse.julialang.org/t/gridap-use-for-finite-element-modelling-for-electrochemical-electrode-modelling/135377)

<div class="topic-metadata">

**Author:** [@algoking](https://discourse.julialang.org/u/algoking)\
**Replies:** 1\
**Last updated:** [June 17, 2026, 12:35pm UTC](https://discourse.julialang.org/t/gridap-use-for-finite-element-modelling-for-electrochemical-electrode-modelling/135377 "2026-06-17T12:35:11Z")

</div>

Hi everyone, I am currently transitioning our lab’s electrochemical modeling workflow from COMSOL to Gridap.jl. My goal is to move away from proprietary licenses and leverage the flexibility of the Julia ecosystem. The…

---

## [Projection of Gradient of Tensor object](https://discourse.julialang.org/t/projection-of-gradient-of-tensor-object/135467)

<div class="topic-metadata">

**Author:** [@Ankan\_Man](https://discourse.julialang.org/u/Ankan_Man)\
**Replies:** 3\
**Last updated:** [June 17, 2026, 12:31pm UTC](https://discourse.julialang.org/t/projection-of-gradient-of-tensor-object/135467 "2026-06-17T12:31:26Z")

</div>

Hi all. I am having an issue with projecting the derivative of a tensor on a sphere. This is the term in the weak form. Let P be the projector ( P = I - nxn). How to properly do the projection. Please help term = ∇(q) ⊙…

---

## [How to use Autodiff in Gridap.jl](https://discourse.julialang.org/t/how-to-use-autodiff-in-gridap-jl/131652)

<div class="topic-metadata">

**Author:** [@Sigmund](https://discourse.julialang.org/u/Sigmund)\
**Replies:** 4\
**Last updated:** [August 23, 2025, 5:45pm UTC](https://discourse.julialang.org/t/how-to-use-autodiff-in-gridap-jl/131652 "2025-08-23T17:45:57Z")

</div>

TLDR: I want to solve an optimal control problem using automatic differentiation (Gridap uses ForwardDiff.jl), but i get an error when i try to find the gradient of the objective function. The objective function depends …

---

## [Rrule for zygote](https://discourse.julialang.org/t/rrule-for-zygote/131069)

<div class="topic-metadata">

**Author:** [@mary](https://discourse.julialang.org/u/mary)\
**Replies:** 7\
**Last updated:** [July 29, 2025, 1:37am UTC](https://discourse.julialang.org/t/rrule-for-zygote/131069 "2025-07-29T01:37:23Z")

</div>

Hi, I am using rrule for gradient calculation in zygote. I defined a function which calculates the gradients and I just call that function inside the entire gradient calculation. Can zygote handle this type of rule? fun…

---

## [Gridap.jl's Linear Elasticity Problem: Access to Global and Local Stiffness matrixes](https://discourse.julialang.org/t/gridap-jls-linear-elasticity-problem-access-to-global-and-local-stiffness-matrixes/130544)

<div class="topic-metadata">

**Author:** [@Van\_Sy\_Tnut](https://discourse.julialang.org/u/Van_Sy_Tnut)\
**Replies:** 2\
**Last updated:** [July 10, 2025, 10:53pm UTC](https://discourse.julialang.org/t/gridap-jls-linear-elasticity-problem-access-to-global-and-local-stiffness-matrixes/130544 "2025-07-10T22:53:29Z")

</div>

Hello everyone! I solved the Linear elasticity problem for a cantilever beam. Now I want to compute the compliance of structures as follows: c = \\mathbf{U}^T \\mathbf{K} \\mathbf{U} = \\sum\_{e=1}^{N} \\mathbf{u}\_e^T \\…

---

## [Gridap.jl: Add tags to faces of 3D models](https://discourse.julialang.org/t/gridap-jl-add-tags-to-faces-of-3d-models/130526)

<div class="topic-metadata">

**Author:** [@Van\_Sy\_Tnut](https://discourse.julialang.org/u/Van_Sy_Tnut)\
**Replies:** 6\
**Last updated:** [July 7, 2025, 6:48pm UTC](https://discourse.julialang.org/t/gridap-jl-add-tags-to-faces-of-3d-models/130526 "2025-07-07T18:48:38Z")

</div>

Hello everyone, I am new to Gridap.jl. I am creating a 3D model of a cantilever beam to apply a distributed load on the right face, and the left face is fixed. Do you know how to add tags to LEFT and RIGHT faces ? Her…

---

## [NLOPT constraint violation](https://discourse.julialang.org/t/nlopt-constraint-violation/128851)

<div class="topic-metadata">

**Author:** [@mary](https://discourse.julialang.org/u/mary)\
**Replies:** 6\
**Last updated:** [May 24, 2025, 9:11pm UTC](https://discourse.julialang.org/t/nlopt-constraint-violation/128851 "2025-05-24T21:11:49Z")

</div>

Hi I am using NLOP for topology optimization. First I did the deterministic topology optimization with constraint on volume, Now I am adding another constraint. As I checked the values for constraint it seems that the d…

---

## [Von mises stress](https://discourse.julialang.org/t/von-mises-stress/127393)

<div class="topic-metadata">

**Author:** [@mary](https://discourse.julialang.org/u/mary)\
**Replies:** 0\
**Last updated:** [March 26, 2025, 9:34pm UTC](https://discourse.julialang.org/t/von-mises-stress/127393 "2025-03-26T21:34:55Z")

</div>

Hi, I am using gridap in julia to find the vonMises stress. As it is for topology optimization I penalized the E for material distribution. It is working correctly when I have unifor material distribution but it is not s…

---

## [Applying Dirichlet boundary conditions to assembled forcing terms](https://discourse.julialang.org/t/applying-dirichlet-boundary-conditions-to-assembled-forcing-terms/127092)

<div class="topic-metadata">

**Author:** [@Simons](https://discourse.julialang.org/u/Simons)\
**Replies:** 1\
**Last updated:** [March 18, 2025, 12:56pm UTC](https://discourse.julialang.org/t/applying-dirichlet-boundary-conditions-to-assembled-forcing-terms/127092 "2025-03-18T12:56:32Z")

</div>

Hi, I’m interested in solving a sequence of finite element problems a(u\_n,v) = b\_n(v) (A x\_n = b\_n in assembled form), all of which have the same boundary conditions. Since A is constant, I want to avoid re-assembling A…

---

## [Building mass and stiffness matrix for time dependent PDE with Gridap](https://discourse.julialang.org/t/building-mass-and-stiffness-matrix-for-time-dependent-pde-with-gridap/126164)

<div class="topic-metadata">

**Author:** [@Cirdans-Home](https://discourse.julialang.org/u/Cirdans-Home)\
**Replies:** 0\
**Last updated:** [February 21, 2025, 5:29pm UTC](https://discourse.julialang.org/t/building-mass-and-stiffness-matrix-for-time-dependent-pde-with-gridap/126164 "2025-02-21T17:29:58Z")

</div>

Hi, I have implemented an algorithm for the solution of system of ODEs that I want to test against a method of line discretization of a PDE. My routine needs to take as input the mass matrix (assumed to be time-indepen…

---

## [Order for finite elements when using Gridap and Gmsh](https://discourse.julialang.org/t/order-for-finite-elements-when-using-gridap-and-gmsh/125094)

<div class="topic-metadata">

**Author:** [@mikeliux](https://discourse.julialang.org/u/mikeliux)\
**Replies:** 9\
**Last updated:** [January 27, 2025, 8:22am UTC](https://discourse.julialang.org/t/order-for-finite-elements-when-using-gridap-and-gmsh/125094 "2025-01-27T08:22:18Z")

</div>

I am experimenting with Gridap package for solving partial differential equations (PDEs) in Julia. I am creating my meshes with GMSH, using the API provided by the Gmsh package in Julia. I save them as \*.msh files, and t…

---

## [GridapGmsh on gmsh.jl object](https://discourse.julialang.org/t/gridapgmsh-on-gmsh-jl-object/82681)

<div class="topic-metadata">

**Author:** [@chupin](https://discourse.julialang.org/u/chupin)\
**Replies:** 2\
**Last updated:** [January 25, 2025, 9:17pm UTC](https://discourse.julialang.org/t/gridapgmsh-on-gmsh-jl-object/82681 "2025-01-25T21:17:53Z")

</div>

I would like to generate a mesh from a set of points defining a contour computed by a Julia program and then to solve a PDE on the generated mesh. I found the package Gmsh.jl to use gmsh program to build a msh file. Th…

---

## [Unit tangent vector in Gridap.jl](https://discourse.julialang.org/t/unit-tangent-vector-in-gridap-jl/108181)

<div class="topic-metadata">

**Author:** [@andy45](https://discourse.julialang.org/u/andy45)\
**Replies:** 4\
**Last updated:** [January 7, 2025, 8:38am UTC](https://discourse.julialang.org/t/unit-tangent-vector-in-gridap-jl/108181 "2025-01-07T08:38:16Z")

</div>

Hi. I am trying to solve two-dimensional Stokes-Darcy equations using Gridap.jl. One of the terms in a weak formulation has the form {\\int\_{I}\\lambda\\left(u\\cdot\\tau\\right)\\left(v\\cdot\\tau\\right)ds} where \\tau is a unit …

---

## [Gridap & Richards equation](https://discourse.julialang.org/t/gridap-richards-equation/123961)

<div class="topic-metadata">

**Author:** [@Fabio\_Zottele](https://discourse.julialang.org/u/Fabio_Zottele)\
**Replies:** 5\
**Last updated:** [December 24, 2024, 10:58pm UTC](https://discourse.julialang.org/t/gridap-richards-equation/123961 "2024-12-24T22:58:30Z")

</div>

Hi all. I am rather new to julia and totally new to Gridap. Before starting a new time and energy consuming project I would like to know if Gridap is suitable for solving “highly non linear problem” (the Richards equatio…

---

## [Confusion about how to use Gridap.jl Dirichlet boundary specification](https://discourse.julialang.org/t/confusion-about-how-to-use-gridap-jl-dirichlet-boundary-specification/123861)

<div class="topic-metadata">

**Author:** [@TheHedgehog2000](https://discourse.julialang.org/u/TheHedgehog2000)\
**Replies:** 2\
**Last updated:** [December 16, 2024, 4:04am UTC](https://discourse.julialang.org/t/confusion-about-how-to-use-gridap-jl-dirichlet-boundary-specification/123861 "2024-12-16T04:04:32Z")

</div>

I am trying to numerically solve the diffusion equation using the Gridap.jl finite element method package. Specifically the problem is radially symmetric diffusion in 3D of a substance with initial concentration C(a \< r \<…

---

## [Problem installing Gridap.jl Tutorials](https://discourse.julialang.org/t/problem-installing-gridap-jl-tutorials/121306)

<div class="topic-metadata">

**Author:** [@uri](https://discourse.julialang.org/u/uri)\
**Replies:** 0\
**Last updated:** [October 14, 2024, 9:07pm UTC](https://discourse.julialang.org/t/problem-installing-gridap-jl-tutorials/121306 "2024-10-14T21:07:57Z")

</div>

I followed all the steps to install the Gridap.jl Tutorials, but when I try to instantiate the project it didin’t precompile 11 dependencies: (Tutorials) pkg\> instantiate Precompiling project… ✗ Algoim ✗ Conda ✗ Min…

---

## [Compliance on displacement control model](https://discourse.julialang.org/t/compliance-on-displacement-control-model/120934)

<div class="topic-metadata">

**Author:** [@mary](https://discourse.julialang.org/u/mary)\
**Replies:** 1\
**Last updated:** [October 7, 2024, 6:49pm UTC](https://discourse.julialang.org/t/compliance-on-displacement-control-model/120934 "2024-10-07T18:49:28Z")

</div>

Hi, I have a domain with applied displacement BC. To find the compliance I read this in a paper “due to equilibrium requirements and the use of displacement control, the components of the external force vector, f F , …

---

## [How to Load Prism (Wedge) Elements in Gridap.jl?](https://discourse.julialang.org/t/how-to-load-prism-wedge-elements-in-gridap-jl/119938)

<div class="topic-metadata">

**Author:** [@Skadi](https://discourse.julialang.org/u/Skadi)\
**Replies:** 0\
**Last updated:** [September 27, 2024, 5:30am UTC](https://discourse.julialang.org/t/how-to-load-prism-wedge-elements-in-gridap-jl/119938 "2024-09-27T05:30:15Z")

</div>

Hello, I am working on solving PDEs using Gridap.jl, specifically on a 3D mesh with 6-node prism (wedge) elements. I converted my original mesh(with node coordinates and connectivity matrix) to a .msh file and tried to …

---

## [Coupled, non-linear, time dependant system of PDE, finite element method, gridap](https://discourse.julialang.org/t/coupled-non-linear-time-dependant-system-of-pde-finite-element-method-gridap/119271)

<div class="topic-metadata">

**Author:** [@karthikeyan98pdy](https://discourse.julialang.org/u/karthikeyan98pdy)\
**Replies:** 6\
**Last updated:** [September 12, 2024, 8:01am UTC](https://discourse.julialang.org/t/coupled-non-linear-time-dependant-system-of-pde-finite-element-method-gridap/119271 "2024-09-12T08:01:54Z")

</div>

New to Julia gridap Personal context I am a phd student who works in numerical characterisation of electrochemical performance of fuel cells/electrolysis cells. This involves resolution of a system of coupled, non line…

---

## [Passive elements implementation in helmholtz PDE](https://discourse.julialang.org/t/passive-elements-implementation-in-helmholtz-pde/119288)

<div class="topic-metadata">

**Author:** [@mary](https://discourse.julialang.org/u/mary)\
**Replies:** 0\
**Last updated:** [September 11, 2024, 4:52pm UTC](https://discourse.julialang.org/t/passive-elements-implementation-in-helmholtz-pde/119288 "2024-09-11T16:52:55Z")

</div>

Hi, I am using gridap to solve helmholtz PDE. I have some passive elements which has fixed values of solution there. I have defined this elements as Dirichlet BC as below in two ways once fixing those elements surface an…

---

## [Adjoint vector boundary condition](https://discourse.julialang.org/t/adjoint-vector-boundary-condition/118149)

<div class="topic-metadata">

**Author:** [@mary](https://discourse.julialang.org/u/mary)\
**Replies:** 1\
**Last updated:** [August 15, 2024, 7:31pm UTC](https://discourse.julialang.org/t/adjoint-vector-boundary-condition/118149 "2024-08-15T19:31:48Z")

</div>

Hi, I am using Gridap to find adjoint vectors in finite element space. Assume that I have a beam with applied displacement as boundary condition on a line. In this case I got discontinuities in values of adjoint vectors.…

---

## [SingularException(0) error in affineFEoperator](https://discourse.julialang.org/t/singularexception-0-error-in-affinefeoperator/117957)

<div class="topic-metadata">

**Author:** [@mary](https://discourse.julialang.org/u/mary)\
**Replies:** 0\
**Last updated:** [August 8, 2024, 4:04pm UTC](https://discourse.julialang.org/t/singularexception-0-error-in-affinefeoperator/117957 "2024-08-08T16:04:06Z")

</div>

Hi I am using gridap for topology optimisation based on gridap tutorial 18. Based on the tutorial there are two domains for problem one for design variable and one another for entire domain. I did the same thing and i go…

---

## [Error while simulating electrostatic problem for a multi-dielectric system using Gridap](https://discourse.julialang.org/t/error-while-simulating-electrostatic-problem-for-a-multi-dielectric-system-using-gridap/116044)

<div class="topic-metadata">

**Author:** [@balaji\_sriram](https://discourse.julialang.org/u/balaji_sriram)\
**Replies:** 5\
**Last updated:** [June 22, 2024, 5:27pm UTC](https://discourse.julialang.org/t/error-while-simulating-electrostatic-problem-for-a-multi-dielectric-system-using-gridap/116044 "2024-06-22T17:27:00Z")

</div>

I am trying to solve an electrostatic poissons equation with 2 different materials. I am trying to compute the electric potential for a sphere (ϵr= 10) embedded inside a box (ϵr= 1). I am getting the below error at th…

---

## [Solidworks output from final desiggn](https://discourse.julialang.org/t/solidworks-output-from-final-desiggn/115196)

<div class="topic-metadata">

**Author:** [@mary](https://discourse.julialang.org/u/mary)\
**Replies:** 3\
**Last updated:** [June 4, 2024, 9:52pm UTC](https://discourse.julialang.org/t/solidworks-output-from-final-desiggn/115196 "2024-06-04T21:52:21Z")

</div>

Hi , I am doing topology optimization using gridap. I want the final design in solidworks format to make it ready for 3d printing. i have my final design as density field. how can i have the solidworks output? thank you …

---

## [Extracting neumann boundary in Gridap - discrepancy](https://discourse.julialang.org/t/extracting-neumann-boundary-in-gridap-discrepancy/114179)

<div class="topic-metadata">

**Author:** [@DnBgk](https://discourse.julialang.org/u/DnBgk)\
**Replies:** 0\
**Last updated:** [May 12, 2024, 10:12pm UTC](https://discourse.julialang.org/t/extracting-neumann-boundary-in-gridap-discrepancy/114179 "2024-05-12T22:12:54Z")

</div>

So I want to model the Neumann-to-Dirichlet map in a Poisson like equation. If I can give it my neumann boundary right away is there an implemented method that also extracts the neumann boundary values? If no. I’m wond…

---

## [1D heat transfer code issues](https://discourse.julialang.org/t/1d-heat-transfer-code-issues/113520)

<div class="topic-metadata">

**Author:** [@Mishal](https://discourse.julialang.org/u/Mishal)\
**Replies:** 2\
**Last updated:** [April 30, 2024, 11:13am UTC](https://discourse.julialang.org/t/1d-heat-transfer-code-issues/113520 "2024-04-30T11:13:06Z")

</div>

Hi Guys Please refer to my code below. When trying to solve I get an error on the last line of the code. ERROR: MethodError: no method matching a(::Gridap.FESpaces.SingleFieldFEBasis{Gridap.FESpaces.TestBasis, Referen…

---

## [Anyone has a starter guide on finite element analysis?](https://discourse.julialang.org/t/anyone-has-a-starter-guide-on-finite-element-analysis/112894)

<div class="topic-metadata">

**Author:** [@Tarny\_GG\_Channie](https://discourse.julialang.org/u/Tarny_GG_Channie)\
**Replies:** 5\
**Last updated:** [April 29, 2024, 12:22pm UTC](https://discourse.julialang.org/t/anyone-has-a-starter-guide-on-finite-element-analysis/112894 "2024-04-29T12:22:45Z")

</div>

After exploring several ideas, I think the idea I’m going to implement would be to simulate air pressure in a musical instrument or vocal tract to synthesize voice. I found finite-element method to be suitable for this a…

---

## [How to define some predefined values to some part of the domain in gridap](https://discourse.julialang.org/t/how-to-define-some-predefined-values-to-some-part-of-the-domain-in-gridap/113254)

<div class="topic-metadata">

**Author:** [@mary](https://discourse.julialang.org/u/mary)\
**Replies:** 0\
**Last updated:** [April 19, 2024, 9:38pm UTC](https://discourse.julialang.org/t/how-to-define-some-predefined-values-to-some-part-of-the-domain-in-gridap/113254 "2024-04-19T21:38:56Z")

</div>

Hi, I have a domain and I want to solve the pde to get the displacement and phase field. meanwhile I want to set the value of phase field in 3 surfaces near the supports and load line as 1 (s=1) I wrote this in julia u…

---

## [How to construct a matrix of gradients depending on nodal locations in gridap](https://discourse.julialang.org/t/how-to-construct-a-matrix-of-gradients-depending-on-nodal-locations-in-gridap/113255)

<div class="topic-metadata">

**Author:** [@mary](https://discourse.julialang.org/u/mary)\
**Replies:** 0\
**Last updated:** [April 19, 2024, 9:52pm UTC](https://discourse.julialang.org/t/how-to-construct-a-matrix-of-gradients-depending-on-nodal-locations-in-gridap/113255 "2024-04-19T21:52:55Z")

</div>

Hi, I want to calculate the gradients of residuals(displacement) with respect to another vector. based on mathematical calculations, as residuals are a vector this gradient should be a matrix. This matrix should has val…

[Next page](https://discourse.julialang.org/tag/gridap/551.md?match_all_tags=true&page=1&tags%5B%5D=gridap)