sub exp {
    #Change all numbers in string to exponental 
    #string has name=value pairs
    my ($string) = @_;

    for ($string) {
        s/\dT\s/e12/g;
        s/\dG\s/e9/g;
        s/\dM\s/e6/g;
        s/\dK\s/e3/g;
        s/\dm\s/e-3/g;
        s/\du\s/e-6/g;
        s/\dp\s/e-12/g;
        s/\df\s/e-15/g;
        s/\dn\s/e-9/g;
        s/=(\S+)\s/sprintf("=%e ",$1)/e;
    }
    return ($string);
}