Serious bug in code word2vec.

[andy-soft]

When you calculate the _expTable, in file Word2Vec.cs line 88 you use a bad issued integer division, and this yields always 0 if the numerator is less than numerator, which is always true, revise the calculated Exptable, all elements are the same. The solution is simple and is casting the ExpTableSize to double:
(other more elegant is to precompute is and define as a double constant, but this is used only on initialization) Also I would have done this as a static table, so if you use the class in a library more than once, you don't need to recalc the exptable every time (provided sizes are the same)
code from line 86 (aprox.)

for (var i = 0; i < ExpTableSize; i++)
            { 
                _expTable[i] = (float)Math.Exp((i / (double)ExpTableSize * 2 - 1) * MaxExp); // Precompute the exp() table
                _expTable[i] = _expTable[i] / (_expTable[i] + 1); // Precompute f(x) = x / (x + 1)
            }

NOTE: this kind of errors (integer divisions rendered as integer, and thought as floating point) are rather common on porting from C++, be careful, I am still searching the code for them!

[GuntaButya]

I have fixed and committed a new Push - Thank You for pointing out this error.

Gunt