public void AbsKFromDelta_Facts() { var vol = 0.32; var fwd = 100.0; var k = 115.0; var t = 1.5; var deltaK = Qwack.Options.BlackFunctions.BlackDelta(fwd, k, 0, t, vol, OptionType.C); Assert.Equal(k, (double)BlackFunctions.AbsoluteStrikeFromDelta(t, deltaK, fwd, vol, 0), 12); }