Why any parameter is not used in the line below?

I've read through the internet and have found that sse has 4 parameters. They are: net,t,y,ew. But why any parameter isn't use in the line below?

net.trainParam.perf = 'sse';

Please help me.

Answer 1

[Jan]

Because in this line, only the string 'sse' is assigned to the field 'perf'.