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For complicated geometries, you probably need some kind of a devoted CAD tool rather than a built-in Matlab functionality. GMSH is a nice open-source tool, and this is my weapon of choice for such problems. Now, there is nothing specific about nested geometries in GMSH that should be reflected in the documentation. You might want to get familiar with basic ...


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A quick note on the .stl for 3D modelling: As noted in the documentation here (Limitations at the bottom) for 3D models MATLAB cannot recognise multi-domains from 3D STL files. If two objects share common points, each is stored in a separate cell, essentially making objects disconnected analytically with no shared mesh/common interface between the two. ...


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I think you have a problem due to a misunderstanding of how ODE45 works. If I'm understanding your problem correctly, you want to plot the behavior at certain times, but you are concerned that you can't do this with ODE45. This is a misunderstanding of how ODE45 works. ODE45 uses adaptive time-stepping, and will never use the time array you give it. It will ...


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I think the problem with initial conditions is more related with the sum of very small numbers with other that are only small (I suspect the problem resides in terms like gam^8, since gam is small). The resulting numeric inaccuracy will bring problems. I've played around with other initial conditions and integration times and in octave (that is similar but ...


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Now that I know more search terms I found this. It is effectively what I wanted to do. https://scicomp.stackexchange.com/a/14352/33469


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Below is from a Professor's answer. No. It is straightforward to check this. west0479 resides in the demos folder where all such samples are kept. >> which west0479.mat C:\Program Files\MATLAB\R2019b\toolbox\matlab\demos\west0479.mat We can get a list of the .mat files in this folder which might contain sparse matrices. >> files = dir(...


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A = bucky(), for instance.  


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There are many sparse matrices in Matrix Market A visual repository of test data for use in comparative studies of algorithms for numerical linear algebra, featuring nearly 500 sparse matrices from a variety of applications, as well as matrix generation tools and services. Use Matrix Market in conjunction with MM_TO_MSM: Matrix Market File to ...


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Defining current density in this system can be done by considering the average current density within the winding region, $J_{0}$ (then subdividing this into elements). For winding height h, Inner cross section $L_{1}$, Outer cross section $L_{2}$ with N turns carrying current I: $ J_{0} = \frac{IN}{h(L_{2} - L_{1})/2} $. I note this expression does not ...


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I think you are using a downwind- instead of an upwind finite difference. This leads to your code imposing a boundary condition where it is not allowed. The solution to your convection equation is basically (ignoring the left BC for the moment) $$ C(x,t) = C_0(x - v t) $$ where $C_0$ is your initial value. Thus, if $v > 0$, it is a rightward travelling ...


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