Ansys Learning Forum Forums Discuss Simulation Photonics Help me to solve this error “NS_nuderiv is not a valid function”. Reply To: Help me to solve this error “NS_nuderiv is not a valid function”.

Amrita Pati
Ansys Employee

Hi Avishek,

Thanks for sharing the article details. I had a look at the vpd_3dB_bandwidth.lsf script file. Line 16 has the name "vpd_nuderiv;" This is a function which is already present in the same directory and we are calling it from vpd_3dB_bandwidth.lsf  script. But the function name in Line 16 in your screenshot has a different name, as a result you see this error. I will recommend changing the name to the original name.

Regards,
Amrita