Program options default has unreasonable precision

Source code:
``` int i,e,t,d;
time_t now,then;
double tolerance,stageTolerance,areadone,rmsadj;
bool done=false;
string inputFile,outputFile;
bool validArgs,validCmd=true;
po::options_description generic("Options");
po::options_description hidden("Hidden options");
po::options_description cmdline_options;
po::positional_options_description p;
po::variables_map vm;
generic.add_options()
("tolerance,t",po::value(&tolerance)->default_value(0.1),"Vertical tolerance")
("output,o",po::value(&outputFile),"Output file");
hidden.add_options()
("input",po::value(&inputFile),"Input file");
p.add("input",1);
cmdline_options.add(generic).add(hidden);
//...
cout<