Encounter problem while using function "fitcsvm"

Hello,I'm a user of MATLAB2021a.

Recently,I'm doing a project on FPGA. I manage to design a SVM classifier module using C lannguage and VitisHLS(converting C to Verilog).

I have already understood how SVM works, but it turns out the result MATLAB predicted is different from what I got with my own decision function 。

is there anyone can explain what's going on?

Thanks.