## No result after successful calculation

A discussion forum for Hydrus-1D users.
Sasan
Posts: 7
Joined: Fri Jun 22, 2018 3:15 am
Location: USA

### No result after successful calculation

Hi

I have been using inverse approach to simulate change of head with rainfall event for a specific period. In this approach, I ask software to estimate alpha, Ks, n, and l. At the end of calculation, software gives this message: "Calculations have finished successfully". However, I can not see the simulation results after pressing enter (attached photo). May you please help me solving this problem. Thank you in advance.
Attachments
Calculation.png (78.89 KiB) Viewed 1986 times

Jirka
Posts: 5268
Joined: Sat Mar 16, 2002 3:47 pm
Location: USA
Location: Riverside, CA

### Re: No result after successful calculation

I cannot see how this could happen. Can you post your project? J.

Sasan
Posts: 7
Joined: Fri Jun 22, 2018 3:15 am
Location: USA

### Re: No result after successful calculation

Jirka wrote:
Fri Sep 27, 2019 2:24 pm
I cannot see how this could happen. Can you post your project? J.
Thank you for the prompt reply. I solved this problem. However, I have faced another problem. After doing inversion, the minimum predicted head is about -100 cm. This seems the software sets the saturated head equal to -100 cm (not 0 cm). On the other word, the upper limit for head is -100 cm not 0 cm. How can I fix this problem so that the upper limit for head approaches 0 cm? Thank you again for your help.
Attachments
Saturation limit.png (34.37 KiB) Viewed 1980 times

Jirka
Posts: 5268
Joined: Sat Mar 16, 2002 3:47 pm
Location: USA
Location: Riverside, CA

### Re: No result after successful calculation

HYDRUS does not recognize any upper limit on the pressure head. It has upper and lower limits only for the Atmospheric BC. J.

Dani
Posts: 12
Joined: Mon Jan 13, 2020 12:43 pm
Location: Germany

### Re: No result after successful calculation

Hi,

I have the same problem (see attached document), and so far I still have solved, It did not have this problem for similar models. Any idea how to solve will be helpful, maybe it is just a dumb mistake.

Thanks

Best regards,
Dani
Attachments
No result.zip

Jirka
Posts: 5268
Joined: Sat Mar 16, 2002 3:47 pm
Location: USA
Location: Riverside, CA

### Re: No result after successful calculation

The problem is badly defined. It’s impossible to estimate five soil hydraulic parameters from the solute BTC for a column with constant flux conditions. J.

Dani
Posts: 12
Joined: Mon Jan 13, 2020 12:43 pm
Location: Germany

### Re: No result after successful calculation

Oh, I did not know that. Might I ask you how do you know that it is badly defined. I mean I know that If I have an unknown I will need 1 equation, if I have 5 unknowns then 5 equations (that are linear independent between them). So I wonder, how can I know (before hand) if it is well or bad defined? And why it is sometimes working for similar set-ups(E.g. attached files Results --> works and No results --> does not work).

Thanks
Attachments
Results.zip

Jirka
Posts: 5268
Joined: Sat Mar 16, 2002 3:47 pm
Location: USA
Location: Riverside, CA

### Re: No result after successful calculation

I think you should read some texts on Uniqueness, identifiability, stability, and ill-posedness of the inverse solution. We have written some texts on the topic (see below). You cannot expect to be able to fit parameters that do not affect the measured data. J.

Šimůnek, J., and J. W. Hopmans, Parameter Optimization and Nonlinear Fitting, In: Methods of Soil Analysis, Part 4, Physical Methods, Chapter 1.7, Eds. J. H. Dane and G. C. Topp, Third edition, SSSA, Madison, WI, 139-157, 2002.

Hopmans, J. W., J. Šimůnek, N. Romano, and W. Durner, Inverse Modeling of Transient Water Flow, In: Methods of Soil Analysis, Part 4, Physical Methods, Chapter 3.6.2, Eds. J. H. Dane and G. C. Topp, Third edition, SSSA, Madison, WI, 963-1008, 2002.

Šimůnek, J., M. Th. van Genuchten, D. Jacques, J. W. Hopmans, M. Inoue, and M. Flury, Solute Transport During Variably-Saturated Flow - Inverse Methods, In: Methods of Soil Analysis, Part 4, Physical Methods, Chapter 6.6, Eds. J. H. Dane and G. C. Topp, Third edition, SSSA, Madison, WI, 1435-1449, 2002.

Šimůnek, J., M. Th. van Genuchten, and M. Šejna, HYDRUS: Model use, calibration and validation, Special issue on Standard/Engineering Procedures for Model Calibration and Validation, Transactions of the ASABE, 55(4), 1261-1274, 2012.

Dani
Posts: 12
Joined: Mon Jan 13, 2020 12:43 pm
Location: Germany

Thanks