double compare

http://stackoverflow.com/questions/356807/java-double-comparison-epsilon

http://stackoverflow.com/questions/4787125/evaluate-if-two-doubles-are-equal-based-on-a-given-precision-not-within-a-certa

https://msdn.microsoft.com/ru-ru/library/9cczk1sc(v=vs.110).aspx

https://msdn.microsoft.com/ru-ru/library/ya2zha7s(v=vs.110).aspx