This keyword sets the extra weight \(\lambda_s\) of the loss term associated with the shear virials in the loss function. The syntax is:

lambda_shear <weight>

Here, <weight> represents \(\lambda_s\), which must satisfy \(\lambda_s \geq 0\) and defaults to \(\lambda_s = 1\). The weight for the shear virials is thus \(\lambda_v \lambda_s\), where \(\lambda_v\) is set by the lambda_v keyword. We have tested that a value of \(\lambda_s=5\) is sometimes helpful to make the prediction of shear moduli more accurate.