Save ovf2 avery time step

[Nikolai Khokhlov]

Hi Serban!

It is a great software, more pleasant in use, compared to OOMMF, for me personally. 

But OOMMF has a schedule option for safe 3D magnetization distribution at every particular time step. In Boris I found it for images only with saveimagefile.

How to make the same for ovf2 files? I tried saveovf2, but it saves one state only.

My script in Python is:

ns.setode('LLG', 'RK4')

time_step =  50e-15
ns.setdt(time_step)

ns.editdatasave(0, 'time', time_step*100)
ns.saveovf2('text', output_file)

ns.run()

[Serban Lepadatu]

Hi Nikolai,

You have 2 options. 

1. Use command buffering (buffer the saveovf2mag command) - see v3.8 manual pt. 274, for exactly this example

2. Use embedded Python scripting mode which allows you to implement a custom data saving schedule with a function defined in Python (see end of Tutorial 9 on embedded Python scripting).

Regards,

Serban

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[Nikolai Khokhlov]

Thank you, Serban!

1st option works perfectly!

[Art]

Hi Nikolai,

How did you do it?. I currently use the following instructions:

ns.adddata('commbuf')
ns.editstagestop(0, 'time', 10e-9)
ns.editdatasave(0, 'time', 1e-10)
ns.saveovf2mag('Domain_%time%.ovf' , bufferCommand = True)

But it usually saves 3 files for each time step. For example, for t=1e-10, Boris saves files at times of 1.01e-10, 9.9e-11 and 1.023e-10.

[Serban Lepadatu]

I'm guessing you're running this with the default RKF45 evaluation method? Since this is an adaptive time-step method, it will save at times as close as possible to the indicated 1e-10 saving increment.

If you want to guarantee saving only at those increments then switch to a fixed time-step method (RK4) with a suitable small enough time-step (setdt command).

https://groups.google.com/d/msgid/boris-computational-spintronics/9cbf91db-242b-4846-bab3-e603c4379a42n%40googlegroups.com

.

[Nikolai Khokhlov]

Hi, Art!

I came to same thought. Try to fix time step. Here is my code:

ns.setdata('commbuf')
ns.editstagestop(0, 'time', total_time)

ns.setode('LLG', 'RK4')

time_step =  100e-15
ns.setdt(time_step)
ns.editdatasave(0, 'time', time_step*4)
ns.saveovf2mag('text', f'size_{dims}x{dims}um_mag_%time%.ovf', bufferCommand = True)

[Nikolai Khokhlov]

Just to know. I used Example 30 for Spinwaves as a base for my simulations (I also do in spinwaves area).

[Art]

Hi, 

I have been using RK4 with a fixed time step of 2e14. Boris usually saves multiple files for a similar time interval, the same happens when I use an adaptive solver (like RKF54). Perhaps the issue is that instead of using "ns.setdata('commbuf')", I used "ns.adddata('commbuf')".

thanks

[Serban Lepadatu]

Hi,

I haven't noticed a problem with this, but if you send me a code snippet which produces the problem I can investigate (could it be maybe files are left-over in the output directory from a previous simulation?).

setdata sets output data, deleting all previous entries, whilst adddata appends a new data field to output. Note, in the latest version there's a simpler method to declare all output data at once in a single line (see manual page 271).

Regards,

Serban

https://groups.google.com/d/msgid/boris-computational-spintronics/433d940b-0cfa-4cd6-bb39-06e66053e52an%40googlegroups.com

.

[Art]

Hi Serban,

For example, for the case of a domain wall driven by  a spin current density:

ns.addmodule ('Py', "transport")
ns.setparam ('Py', "P", 0.5)
ns.setparam ('Py', "beta", 0.1)
ns.setparam ('Py', "damping", 0.08)

ns.disabletransportsolver(1)

ns.setode('LLG', 'RK4')

ns.setdt(1e-14)

ns.setcurrentdensity('Py',1,0,0)
ns.loadovf2curr('Py','/home/zwt/Boris/DomainWall/J=5e11.ovf')

ns.setdata('commbuf')
ns.editstagestop(0, 'time', 50e-9)
ns.editdatasave(0, 'time', 2.0e-10)
ns.saveovf2mag('/home/zwt/Boris/DomainWall/J=5e11/DomainWall_%time%.ovf' , bufferCommand = True)

ns.cuda (1)
ns.Run ()

The simulations create the files: DomainWall_0s.ovf  DomainWall_199.98ps.ovf  DomainWall_199.99ps.ovf  DomainWall_200ps.ovf  DomainWall_399.99ps.ovf  DomainWall_400ps.ovf.  To run the simulation I use  /home/zwt/BorisLin -p 1001 -s  /home/zwt/Boris/DomainWall/tst.py &.

[Serban Lepadatu]

Thanks, yes there is a problem when the time saving interval is much larger than the time step, resulting in multiple saves around the time saving point. I fixed it now, so will release an update soon. What you can do for now is save every given iterations (iter), since with fixed time-step you just multiply the iterations by the time-step to get the simulation time (or else save iter and time data as well in the output file).

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