Is there any way to find the initial phase of a section of signal?

[Wenchel]

Given a signal such as:

DiscreteSignal signal = new SineBuilder()
                        .SetParameter("frequency", 500.0/*Hz*/)
                        .SetParameter("phase", Math.PI / 2)
                        .OfLength(10000)
                        .SampledAt(44100/*Hz*/)
                        .Build();

How to find the initial phase pi/2 by NWaves? And how to get frequency 500 by NWaves?