Hi Khalid,

You can switch the PML off by setting the absorption within the layer to zero. You can do this with the input option `'PMLAlpha'`

. You can either set a single number (which controls the PML on all sides), or give a vector in the form `[alpha_x, alpha_y, alpha_z]`

(or `[alpha_x, alpha_z]`

in 2D) which allows control of the PML in different directions.

You can do the same for the PML size, although if you want to switch the PML off you should set `'PMLAlpha'`

to zero rather than `'PMLSize'`

to zero.

The values are set in pairs because the spectral calculation of the spatial derivatives causes waves to wrap from one side to the opposite side of the computational domain. Thus if you set one side of the x-direction PML to zero (for example), a wave leaving the domain would then interact with the PML on the opposite side (in reverse).

I hope that helps, let me know if you have any more questions.

Brad.