negative probability

[shajoezhu]

./hybrid-coal -sp issue17.st -gt issue17.gt
Total probability = -9.67989e-08

joezhu@joezhu-M3800:~/hybrid-coal$ cat issue17.st
((((t5:0.04645784404,(t9:0.01069741008,t2:0.01069741008):0.03576043396):0.05427704712,t3:0.1007348912):0.04830680475,(((t7:0.04074259488,t1:0.04074259488):0.05134702158,t4:0.09208961646):0.04913823565,t8:0.1412278521):0.007813843805):0.0427100704,((t6:0.009568665827,t11:0.009568665827):0.05300883308,t10:0.06257749891):0.1291742674):0.1213331226;

joezhu@joezhu-M3800:~/hybrid-coal$ cat issue17.gt
((((t5,t3),(t9,t2)),(((t7,t1),t4),t8)),((t6,t11),t10));