gfortran -o f90_stiff f90_stiff.f90

#HT100  Sigy=885  Siga=400
#SHY685 Sigy=685  Siga=330
#SM570  Sigy=450  Siga=240
#SM490  Sigy=315  Siga=175
#SM400  Sigy=235  Siga=130
#f90_stiff  DD  t0  Sigy  Siga  tr0  hr  ell
#write(6,'(5f10.3)') DD,t0,Sigy,Siga,Pk
#write(6,'(4f10.3)') tr0,hr,ell,sig_cr/sig_cc

./f90_stiff 4600 29 315 175 20 100 3000