ANN_DBL_MAX = 1.7E+308;
Limits There are a number of places where we use the maximum double value as default initializers (and others may be used, depending on the data/distance representation). These can usually be found in limits.h (as LONG_MAX, INT_MAX) or in float.h (as DBL_MAX, FLT_MAX).
Not all systems have these files. If you are using such a system, you should set the preprocessor symbol ANN_NO_LIMITS_H when compiling, and modify the statements below to generate the appropriate value. For practical purposes, this does not need to be the maximum double value. It is sufficient that it be at least as large than the maximum squared distance between between any two points.