fixed number of modes for ou_kmax

cpp/full_code/ornstein_uhlenbeck_process.cpp

@@ -115,7 +115,7 @@ void ornstein_uhlenbeck_process<rnumber,be>::initialize_B()
             {
                 double kabs = sqrt(ksqu);
                 double sigma;
-                if (ksqu == 0)
+                if (ksqu == 0 || ksqu == this->ou_kmax_squ)
                 {
                     ksqu = 1; kabs = 1; sigma = 0;
                 }