How to use more than a tabulated Burman file in the ASCII model

Dear users
My simulation consist on simulating the mantle flow using 2 distinct compositional fields, one denser than the other. So I created 2 tabulated files using Perplex and Burman

I’ve been able to achieve some results using the Steinberger model, but i think that my work would be much easier if I use the ASCII data model.

The problem is, while in Steinberger i can set more than a tabulated file (set Model file names = peridotite.txt, LLSVP.txt), i cannot do that with the ASCII model. I can create an extra compositional field, but i cannot assign a tabulated file to that field except. I can use only one tabulated file for the whole mantle. Is that a code limitation or there is something i can do to use more than a tabulated file?
If it is not possible, will there be the possibility in the future to usa more than 2 files using the ASCII model?
Thank you for the availability

Dear @Francyrad,

I’ve been able to achieve some results using the Steinberger model, but i think that my work would be much easier if I use the ASCII data model.

Steinberger is a material model - the material models are used in ASPECT to describe how material properties vary as a function of temperature, pressure, composition, strain rate etc. ASCII data isn’t a material model, so it isn’t obvious what you want to use instead of Steinberger.

Steinberger uses equation_of_state/ to define thermodynamic properties. It is currently the only material model that can do this, although you can use Steinberger in the Compositing material model to give you some added options (see tests/compositing_02.prm). Please do read the docs and docstrings to understand what this is able to do - it is possible that you want physics that has not yet been implemented.

If Compositing doesn’t help you, we’ll need more detail about what you need.

Development of ASPECT is driven by the needs of the community of developers - we primarily add things to answer our own scientific questions. But we are always happy to help other users with their own development goals if the work will produce interesting papers!

I apologize if I didn’t make myself clear. What I wanted to say is that I found myself very well using the ASCII model with tables created thanks to Burnman’s Python scripts, just like in the Burnman example of ASPECT.
When I run simulations using this model, I simply find it leaner to run and a viable alternative to the Steinberger model (much heavier).
I used the same table of material for both Steinberger (perplex) and Burnman (after the python conversion), getting very similar results.
The point is that I’m finding it very difficult to find harmony with Steinberger’s model because of the lack of freedom (and computational cost) in choosing the right viscosity profile for my planet. For example, it is not possible to reproduce some CITCOM simulations with Steinberger in the literature if you do not choose an adiabatic profile. I tried for days to reproduce the simulation of a study that used CITCOM starting from a totally isothermal profile (which has a dt at the top and bottom) and with temperature perturbations. Doing it with Steinberger by choosing an isothermal profile and with perturbations is impossible because it would mean having an unrealistic viscosity profile, while instead using the Viscosity prefactors of the ASCII model (along with my material tables) the experiment can be reproduced more easily and at a much lower computational cost.
In addition, with Steinberger it is possible to set more than one compositional field, and each of these compostional fields has its own material table.
Using the ASCII model, although I have set up an additional compositional field, I can only use a material table that applies to both my background mantle and my compositional field, and not two material tables. I wonder then, returning to the original question of this post, if it was possible some workaround (or a future code update) to choose more than one Burnman table in the ASCII material model, each for a different compositional field.

Thank you anyway for the suggestion regarding the choice of compositing model. I had read something about the manual, but not being present in the coockbooks an example I had no idea how to use it, so please add, in a possible future update, a cookbook (also complex) about the compositing model. Now I will try to mix the Steinberger model with some other model to get the desired viscosities. My wish to be able to use two material files on Burnman via the ASCII model still remains on.

Thank you so much for your help and availability


Thanks for the clarification - I now understand that you want to read in several 1D profiles (1D for the sake of faster simulation).

The material model that the BurnMan example uses is ascii reference profile, and the source code for this model can be found here: aspect/source/material_model/ at main · geodynamics/aspect · GitHub. The code can currently only read in one profile.

In my opinion, it is unlikely that any of the existing developers will modify this material model to read several different files soon. However, you could use steinberger as a guide to make the required changes. If you want to try this, I would be happy to give you some advice / a list of things to change.

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I can try! So i’m very happy if you can give me some adivce in way to do a good and correct work