Dear Hanyu,
The code in OptiSystem components take into account when a none-integer value appears. An example if you use number of bits 32768 bits in Dual-polarization 8PSK modulation. In this case, the number of symbols is 5461.333333. Thus, we use internally an integer value in this case.
You may check the example (DP-8PSK back to back.osd) located at the following link.
C:\Users\USER NAME\Documents\OptiSystem 17.1 Samples\Advanced modulation systems\PSK systems\8PSK
Regards,
Ahmad
