Help regarding error message appearing in Optifdtd

Hello,

Within the Input Plane form under the Sine Modulated Pulse tab you are presented with the time and frequency domain representations of the pulse. The frequency spectrum is obtained through an FFT of the time domain. It would appear that whatever settings you are changing are resulting in too many data points within this FFT and it is resorting back to a “safe” number. I have reviewed your design in OptiFDTD 16.0RC and I am unable to find the settings that reproduce the error.

I have 3 questions/requests:

1. Can you confirm for me what version of the product you are using?
2. Can you confirm that this error is occuring within OptiFDTD Designer when you edit the input plane and NOT within OptiFDTD Analyzer after a simulation is run.
3. Is it possible for you to provide me with the sequence of changes you make that will trigger that warning on this design?

Scott

Hello,

Within the Input Plane form under the Sine Modulated Pulse tab you are presented with the time and frequency domain representations of the pulse. The frequency spectrum is obtained through an FFT of the time domain. It would appear that whatever settings you are changing are resulting in too many data points within this FFT and it is resorting back to a “safe” number. I have reviewed your design in OptiFDTD 16.0RC and I am unable to find the settings that reproduce the error.

I have 3 questions/requests:

1. Can you confirm for me what version of the product you are using?
2. Can you confirm that this error is occuring within OptiFDTD Designer when you edit the input plane and NOT within OptiFDTD Analyzer after a simulation is run.
3. Is it possible for you to provide me with the sequence of changes you make that will trigger that warning on this design?

Scott

Based on your feedback it would appear that the designer is using a number that is too large as an assumption within designer as it does not know how long you wish to run the simulation. This would normally not be an issue as the number would never be used except in the instance you go into the input plane window to view the expected pulse shape in time and frequency domain.

This was corrected when the product was migrated to 64-bit so it has been corrected and the latest versions of the product can support the behaviour you are requesting. Please keep in mind that the 32-bit application is an unsupported old version of the product provided as a courtesy when we migrated to 64-bit.

I would advise one of the two following courses of action:

1. Use the functionality with a set number of time steps during editing and then change it to “Run until user stops execution” just before running the simulation. It is important to note that if this error is a function of it being a 32-bit platform and you run it “too long” Analyzer may have similar issues.
2. Do not use “Run until user stops execution” at all and simply set the number of time steps to a value that is large enough to get the results you require. As with #1 note it is possible the issue may show up in Designer again and in Analyzer if you set the number too high.

Scott

Based on your feedback it would appear that the designer is using a number that is too large as an assumption within designer as it does not know how long you wish to run the simulation. This would normally not be an issue as the number would never be used except in the instance you go into the input plane window to view the expected pulse shape in time and frequency domain.

This was corrected when the product was migrated to 64-bit so it has been corrected and the latest versions of the product can support the behaviour you are requesting. Please keep in mind that the 32-bit application is an unsupported old version of the product provided as a courtesy when we migrated to 64-bit.

I would advise one of the two following courses of action:

1. Use the functionality with a set number of time steps during editing and then change it to “Run until user stops execution” just before running the simulation. It is important to note that if this error is a function of it being a 32-bit platform and you run it “too long” Analyzer may have similar issues.
2. Do not use “Run until user stops execution” at all and simply set the number of time steps to a value that is large enough to get the results you require. As with #1 note it is possible the issue may show up in Designer again and in Analyzer if you set the number too high.

Scott