Hi David, I found some strange thing when running the transport model, i.e., sometime the selected output file is empty. Don't know if it is a bug. Look at the small example below, the output fild tmp1 is empty after running in my computer. cheers, xiaomin TITLE Test SOLUTION 1-28 pH 7 charge units mol/kgw pe 4 -water 0.03375 Na 1e-3 Cl 2.9e-03 end SOLUTION 0 Inlet concentration pH 7 units mol/kgw pe 4 -water 0.03375 end TRANSPORT -cells 28 -shifts 50 -time_step 30857 #10.5d/28*86400s/d -flow_direction forward -lengths 28*5e-3 -boundary_conditions flux flux -dispersivities 28*0.012 -correct_disp true -diffusion_coefficient 0.0000 -punch_cells 28 -punch_frequency 1 -warnings false SELECTED_OUTPUT -file tmp1 -selected_out true -user_punch true -reset false PRINT -reset false -selected_output true -status true USER_Graph -start 5 pv=STEP_NO/28 145 ph=-log10(ACT("H+")) 160 PUNCH pv,ph,"1" -end END ======= At 2003-06-26, 07:17:00 you wrote: ======= >I have been working on a method for integrating the rate equations that >works better with stiff equations. I have implemented a package called >CVODE from Lawrence Livermore National Lab as an alternative to the >Runge-Kutta method that should speed up the calculations. This version >should work better when you are trying to simulate equilibrium by using >fast rates, which is the situation in the problem you sent me earlier. You >should be able to use the enclosed version without having to increase the >rate constants to be on the order of the time step. I have done some >preliminary testing and the program seems to work, but you should do some >additional testing to make sure it is working correctly on your problems. >The enclosed program has identical functionality to PHREEQC, except this >version uses CVODE to integrate rate expressions, which could be slower >than RK in some (many?) cases. Please let me know if you find any bugs and, >if you use it, whether it works satisfactorily. > >David > >(See attached file: phreeqc.cvode.exe) > > >David Parkhurst (dlpark@xxxxxxxx) >U.S. Geological Survey >Box 25046, MS 413 >Denver Federal Center >Denver, CO 80225 > >Project web page: https://wwwbrr.cr.usgs.gov/projects/GWC_coupled = = = = = = = = = = = = = = = = = = = = Best regards. xiaomin Mao Institute for Infrastructure and Environment School of Engineering and Electronics The University of Edinburgh Crew Building King's Buildings Edinburgh EH9 3JN United Kingdom Tel: +44 131 650 5810 Fax: +44 131 667 9238 xmao@xxxxxxxxxxxxxxxxxx http://myprofile.cos.com/maoxm 2003-07-01
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