question: public static double expQuick ( final double value ) { if ( USE_JDK_MATH ) { return Math . exp ( value ) ; } return Double . longBitsToDouble ( ( long ) ( int ) ( 1512775.3952 * value + 1.0726481222E9 ) << 32 ) ; }
target:  Quick exp, with a max relative error of about 2.94e-2 for |value| < 700.0 or so, and no accuracy at all outside this range. Derived from a note by Nicol N. Schraudolph, IDSIA, 1998.