* can narrow the possible floor(log10(x)) values to two. For example, if floor(log2(x)) is 6,
     * then 64 <= x < 128, so floor(log10(x)) is either 1 or 2.
     */
    int y = maxLog10ForLeadingZeros[Long.numberOfLeadingZeros(x)];
    /*
     * y is the higher of the two possible values of floor(log10(x)). If x < 10^y, then we want the

		{"IsNaN", Func, 0},
		{"J0", Func, 0},
		{"J1", Func, 0},
		{"Jn", Func, 0},
		{"Ldexp", Func, 0},
		{"Lgamma", Func, 0},
		{"Ln10", Const, 0},
		{"Ln2", Const, 0},
		{"Log", Func, 0},
		{"Log10", Func, 0},
		{"Log10E", Const, 0},
		{"Log1p", Func, 0},
		{"Log2", Func, 0},
		{"Log2E", Const, 0},
		{"Logb", Func, 0},
		{"Max", Func, 0},
		{"MaxFloat32", Const, 0},
		{"MaxFloat64", Const, 0},

function lesserPower(x,opt_base){const base=opt_base||10;return Math.pow(base,Math.floor(logOrLog10(x,base)));}