# Set constants to correct SI (2019) value

The constant `mu0`

, and by extension also `eps0`

and `Z0`

, is slightly wrongly defined. By the 2019 SI standard, `\mu_0 \approx 1.25663706212 \cdot 10^{6} H m^{-1} \neq 4\pi \cdot 10^{-7} H m^{-1}`

.

This MR corrects this, with `eps0`

and `Z0`

still given by their relation to `mu0`

. Additionally, the MR ensures that the value defined in `IW2D.h`

is not overwritten locally in other C++ source files.

While the code in the MR does not depend on !16 (merged), the results presented below and the updated reference data files were calculated with both fixes implemented, in order to not have to update the files twice.

Solves #17 (closed).