Question regarding RCR values

[Alessia Chiofalo]

Dear Simvascular Forum Users,

I am interested in understanding how Simvascular calculates RCR values.

To give more context, let's consider the input file for a 1D ROM that might be generated from SimVascular:

Code: Select all

DATATABLE RCR_0 LIST LEFT_RENAL
0.0 4102.9632
0.0 0.000197
0.0 10550.4768
0.0 0.0
ENDDATATABLE

This file is written in `Python\site-packages\sv_rom_simulation\io_1d.py`, which is interfaced to the C++ source code under `Code\Source\PythonAPI` (the C++ code that I guess directly intercommunicates with the GUI part).

Also, I see there is a TCL core, in which there exist a file `**\Core\calculate_rcr.tcl`.
By the name, I assume it calculates the RCR values, which is exactly my doubt.
I see there is a procedure named "RCR_create_multi_branch_rcrtdat". Where is this procedure called?
I never used TCL as programming language, but I see this procedure reads inputs from a file. Which file? Is there a way to get an example of such file? Is this file generated or is among the base input files that SimVascular requires?

I'd have many other questions (i.e. where the function "RCR_TAC_optimize" is used), but I don't want to make this post too long.

I will close it by reiterating the base question: effectively, how are RCR values computed in SimVascular?
Are they simply input values from a given SimVascluar model (though I doubt it is the case, otherwise I don't see the reason of the above code to be there and be named like that)?
Or, are they computed from other basic quantities, i.e. pressures and flows in each branch? If so, how exactly?

[David Parker]

Hello,

SV does not use TCL code. It is there from a previous implementation and will be removed.

The RCR values are just input into the 1D ROM file from the values entered into the SV GUI.

Cheers,
Dave

[Alessia Chiofalo]

Hi,

thanks. Ok, TCL code is useless. That's why I could not find where those functions were used.

Regarding the 1D ROM Model, I know RCR values are inputs.
I put an extract of the 1D input file to give a bit more context.

RE: "from the values entered into the SV GUI"
So, with this are you stating that RCR values are never computed in any place within SV, but are just model's input?

Thanks

[David Parker]

Hello,

So, with this are you stating that RCR values are never computed in any place within SV, but are just model's input?


Correct!

You will need to determine the appropriate RCR values for the downstream vasculature you are interested in modeling.

Cheers,
Dave