Hi all, I have some questions when I read one of the prj file in TH2M modules’ benchmark which link is the following:

TH2M benchmark

I found there the code of `jacobian_assembler`

part is just like:

`<jacobian_assembler> <type>CentralDifferences</type> <component_magnitudes> 1e6 1e6 1e6 1e6 1e6 1e6 1e6 1e6 300 300 300 300 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 </component_magnitudes> <relative_epsilons> 1e-8 1e-8 1e-8 1e-8 1e-8 1e-8 1e-8 1e-8 1e-8 1e-8 1e-8 1e-8 1e-5 1e-5 1e-5 1e-5 1e-5 1e-5 1e-5 1e-5 1e-5 1e-5 1e-5 1e-5 1e-5 1e-5 1e-5 1e-5 </relative_epsilons> </jacobian_assembler>`

I know that the `compoenet_magnitudes`

represents the representative magnitudes for the components of the solution vector of the process being assembled, which can be accessed from https://doxygen.opengeosys.org/d1/dd2/ogs_file_param__prj__processes__process__jacobian_assembler__centraldifferences__component_magnitudes

But why are there four or eight values for each vector since `pressure`

and `temperature`

are actually scalars? I think there should be only one value for either of them. Second, how to define these magnitudes for all components in this part that looks like a matrix? I read some examples but didn’t figure it out. Can anyone tell me the pattern?

I will appreciate it a lot if anyone can give me some help.