## [Flightgear-devel] JSBSim : potential division by zero error

 [Flightgear-devel] JSBSim : potential division by zero error From: Frederic Bouvier - 2009-06-27 07:58:14 ```Hi Jon, in the code below ( from FGJSBBase.h ), there is a potential divide by zero error reported by the compiler : static double GaussianRandomNumber(void) { static double V1, V2, S; static int phase = 0; double X; V1 = V2 = S = X = 0.0; if (phase == 0) { do { double U1 = (double)rand() / RAND_MAX; double U2 = (double)rand() / RAND_MAX; V1 = 2 * U1 - 1; V2 = 2 * U2 - 1; S = V1 * V1 + V2 * V2; } while(S >= 1 || S == 0); X = V1 * sqrt(-2 * log(S) / S); } else X = V2 * sqrt(-2 * log(S) / S); <<==== S == 0.0 phase = 1 - phase; return X; } Regards, -Fred -- Frédéric Bouvier http://my.fotolia.com/frfoto/ Photo gallery http://fgsd.sourceforge.net/ FlightGear Scenery Designer ```

 [Flightgear-devel] JSBSim : potential division by zero error From: Frederic Bouvier - 2009-06-27 07:58:14 ```Hi Jon, in the code below ( from FGJSBBase.h ), there is a potential divide by zero error reported by the compiler : static double GaussianRandomNumber(void) { static double V1, V2, S; static int phase = 0; double X; V1 = V2 = S = X = 0.0; if (phase == 0) { do { double U1 = (double)rand() / RAND_MAX; double U2 = (double)rand() / RAND_MAX; V1 = 2 * U1 - 1; V2 = 2 * U2 - 1; S = V1 * V1 + V2 * V2; } while(S >= 1 || S == 0); X = V1 * sqrt(-2 * log(S) / S); } else X = V2 * sqrt(-2 * log(S) / S); <<==== S == 0.0 phase = 1 - phase; return X; } Regards, -Fred -- Frédéric Bouvier http://my.fotolia.com/frfoto/ Photo gallery http://fgsd.sourceforge.net/ FlightGear Scenery Designer ```