Time information in ".chk" --> ".dat"
CAUTION: This message came from outside Imperial. Do not click links or open attachments unless you recognise the sender and were expecting this email. Hello, I switched to Nektar++ v5.9.0 some time ago and I am currently having an issue with .chk files when using the Linearized Euler Equations solver. I am using the Checkpoint filter to save .chk files at the desired output frequency. I then convert these .chk files to Tecplot .dat format using the standard FieldConvert workflow. The conversion itself appears to work correctly, and the field data can be opened in Tecplot. However, when I load the resulting .dat files into Tecplot, I do not see any time information associated with them. As a result, I am unable to create animations, because the .dat files are not treated as sequential time instances; instead, each newly loaded file appears to replace the previously loaded one. I also checked a single .dat file corresponding to a later physical time instance, but Tecplot still reports the solution time as 0 s, which is not correct. As a quick check, I opened the .dat file in Notepad++ and noticed that the file header does not appear to contain any time information. I am not sure whether this is the source of the problem, but it seems related. Could you please advise whether the checkpoint files should contain physical time information after conversion to Tecplot format, or whether an additional option is required in FieldConvert to preserve/export this metadata? Any help would be greatly appreciated. Regards, Ishan PGR
Hi Ishan, I believe that your problem is being addressed in the following MR, which hopefully will be merged soon: https://gitlab.nektar.info/nektar/nektar/-/merge_requests/2412 Cheers, Jacques ________________________________ From: Nande, Ishan A. <ian9@leicester.ac.uk> Sent: 24 April 2026 11:29 To: nektar-users <nektar-users@imperial.ac.uk> Subject: [Nektar-users] Time information in ".chk" --> ".dat" CAUTION: This message came from outside Imperial. Do not click links or open attachments unless you recognise the sender and were expecting this email. Hello, I switched to Nektar++ v5.9.0 some time ago and I am currently having an issue with .chk files when using the Linearized Euler Equations solver. I am using the Checkpoint filter to save .chk files at the desired output frequency. I then convert these .chk files to Tecplot .dat format using the standard FieldConvert workflow. The conversion itself appears to work correctly, and the field data can be opened in Tecplot. However, when I load the resulting .dat files into Tecplot, I do not see any time information associated with them. As a result, I am unable to create animations, because the .dat files are not treated as sequential time instances; instead, each newly loaded file appears to replace the previously loaded one. I also checked a single .dat file corresponding to a later physical time instance, but Tecplot still reports the solution time as 0 s, which is not correct. As a quick check, I opened the .dat file in Notepad++ and noticed that the file header does not appear to contain any time information. I am not sure whether this is the source of the problem, but it seems related. Could you please advise whether the checkpoint files should contain physical time information after conversion to Tecplot format, or whether an additional option is required in FieldConvert to preserve/export this metadata? Any help would be greatly appreciated. Regards, Ishan PGR
CAUTION: This message came from outside Imperial. Do not click links or open attachments unless you recognise the sender and were expecting this email. Hello Jacques, Thanks for the information. Yes, this seems to be the issue. I think for now, I will have to figure out a way to assign time from within Tecplot. Regards, Ishan PGR From: Xing, Jacques <j.xing@imperial.ac.uk> Sent: 24 April 2026 11:41 To: Nande, Ishan A. <ian9@leicester.ac.uk>; nektar-users <nektar-users@imperial.ac.uk> Subject: Re: Time information in ".chk" --> ".dat" ***CAUTION:*** This email was sent from an EXTERNAL source. Think before clicking links or opening attachments. Hi Ishan, I believe that your problem is being addressed in the following MR, which hopefully will be merged soon: https://gitlab.nektar.info/nektar/nektar/-/merge_requests/2412 Cheers, Jacques ________________________________ From: Nande, Ishan A. <ian9@leicester.ac.uk<mailto:ian9@leicester.ac.uk>> Sent: 24 April 2026 11:29 To: nektar-users <nektar-users@imperial.ac.uk<mailto:nektar-users@imperial.ac.uk>> Subject: [Nektar-users] Time information in ".chk" --> ".dat" CAUTION: This message came from outside Imperial. Do not click links or open attachments unless you recognise the sender and were expecting this email. Hello, I switched to Nektar++ v5.9.0 some time ago and I am currently having an issue with .chk files when using the Linearized Euler Equations solver. I am using the Checkpoint filter to save .chk files at the desired output frequency. I then convert these .chk files to Tecplot .dat format using the standard FieldConvert workflow. The conversion itself appears to work correctly, and the field data can be opened in Tecplot. However, when I load the resulting .dat files into Tecplot, I do not see any time information associated with them. As a result, I am unable to create animations, because the .dat files are not treated as sequential time instances; instead, each newly loaded file appears to replace the previously loaded one. I also checked a single .dat file corresponding to a later physical time instance, but Tecplot still reports the solution time as 0 s, which is not correct. As a quick check, I opened the .dat file in Notepad++ and noticed that the file header does not appear to contain any time information. I am not sure whether this is the source of the problem, but it seems related. Could you please advise whether the checkpoint files should contain physical time information after conversion to Tecplot format, or whether an additional option is required in FieldConvert to preserve/export this metadata? Any help would be greatly appreciated. Regards, Ishan PGR
Hi Ishan, It has been I while since I have used Tecplot, but I believe it is possible to assign a constant delta time to each .dat file. Cheers, Jacques ________________________________ From: Nande, Ishan A. <ian9@leicester.ac.uk> Sent: 24 April 2026 11:44 To: Xing, Jacques <j.xing@imperial.ac.uk>; nektar-users <nektar-users@imperial.ac.uk> Subject: RE: Time information in ".chk" --> ".dat" CAUTION: This message came from outside Imperial. Do not click links or open attachments unless you recognise the sender and were expecting this email. Hello Jacques, Thanks for the information. Yes, this seems to be the issue. I think for now, I will have to figure out a way to assign time from within Tecplot. Regards, Ishan PGR From: Xing, Jacques <j.xing@imperial.ac.uk> Sent: 24 April 2026 11:41 To: Nande, Ishan A. <ian9@leicester.ac.uk>; nektar-users <nektar-users@imperial.ac.uk> Subject: Re: Time information in ".chk" --> ".dat" ***CAUTION:*** This email was sent from an EXTERNAL source. Think before clicking links or opening attachments. Hi Ishan, I believe that your problem is being addressed in the following MR, which hopefully will be merged soon: https://gitlab.nektar.info/nektar/nektar/-/merge_requests/2412 Cheers, Jacques ________________________________ From: Nande, Ishan A. <ian9@leicester.ac.uk<mailto:ian9@leicester.ac.uk>> Sent: 24 April 2026 11:29 To: nektar-users <nektar-users@imperial.ac.uk<mailto:nektar-users@imperial.ac.uk>> Subject: [Nektar-users] Time information in ".chk" --> ".dat" CAUTION: This message came from outside Imperial. Do not click links or open attachments unless you recognise the sender and were expecting this email. Hello, I switched to Nektar++ v5.9.0 some time ago and I am currently having an issue with .chk files when using the Linearized Euler Equations solver. I am using the Checkpoint filter to save .chk files at the desired output frequency. I then convert these .chk files to Tecplot .dat format using the standard FieldConvert workflow. The conversion itself appears to work correctly, and the field data can be opened in Tecplot. However, when I load the resulting .dat files into Tecplot, I do not see any time information associated with them. As a result, I am unable to create animations, because the .dat files are not treated as sequential time instances; instead, each newly loaded file appears to replace the previously loaded one. I also checked a single .dat file corresponding to a later physical time instance, but Tecplot still reports the solution time as 0 s, which is not correct. As a quick check, I opened the .dat file in Notepad++ and noticed that the file header does not appear to contain any time information. I am not sure whether this is the source of the problem, but it seems related. Could you please advise whether the checkpoint files should contain physical time information after conversion to Tecplot format, or whether an additional option is required in FieldConvert to preserve/export this metadata? Any help would be greatly appreciated. Regards, Ishan PGR
I am not using the filter for now, I am using the parameter command of IO_CheckSteps and it works fine. ________________________________ From: Xing, Jacques <j.xing@imperial.ac.uk> Sent: 24 April 2026 11:47 To: Nande, Ishan A. <ian9@leicester.ac.uk>; nektar-users <nektar-users@imperial.ac.uk> Subject: [Nektar-users] Re: Time information in ".chk" --> ".dat" Hi Ishan, It has been I while since I have used Tecplot, but I believe it is possible to assign a constant delta time to each .dat file. Cheers, Jacques ________________________________ From: Nande, Ishan A. <ian9@leicester.ac.uk> Sent: 24 April 2026 11:44 To: Xing, Jacques <j.xing@imperial.ac.uk>; nektar-users <nektar-users@imperial.ac.uk> Subject: RE: Time information in ".chk" --> ".dat" CAUTION: This message came from outside Imperial. Do not click links or open attachments unless you recognise the sender and were expecting this email. Hello Jacques, Thanks for the information. Yes, this seems to be the issue. I think for now, I will have to figure out a way to assign time from within Tecplot. Regards, Ishan PGR From: Xing, Jacques <j.xing@imperial.ac.uk> Sent: 24 April 2026 11:41 To: Nande, Ishan A. <ian9@leicester.ac.uk>; nektar-users <nektar-users@imperial.ac.uk> Subject: Re: Time information in ".chk" --> ".dat" ***CAUTION:*** This email was sent from an EXTERNAL source. Think before clicking links or opening attachments. Hi Ishan, I believe that your problem is being addressed in the following MR, which hopefully will be merged soon: https://gitlab.nektar.info/nektar/nektar/-/merge_requests/2412 Cheers, Jacques ________________________________ From: Nande, Ishan A. <ian9@leicester.ac.uk<mailto:ian9@leicester.ac.uk>> Sent: 24 April 2026 11:29 To: nektar-users <nektar-users@imperial.ac.uk<mailto:nektar-users@imperial.ac.uk>> Subject: [Nektar-users] Time information in ".chk" --> ".dat" CAUTION: This message came from outside Imperial. Do not click links or open attachments unless you recognise the sender and were expecting this email. Hello, I switched to Nektar++ v5.9.0 some time ago and I am currently having an issue with .chk files when using the Linearized Euler Equations solver. I am using the Checkpoint filter to save .chk files at the desired output frequency. I then convert these .chk files to Tecplot .dat format using the standard FieldConvert workflow. The conversion itself appears to work correctly, and the field data can be opened in Tecplot. However, when I load the resulting .dat files into Tecplot, I do not see any time information associated with them. As a result, I am unable to create animations, because the .dat files are not treated as sequential time instances; instead, each newly loaded file appears to replace the previously loaded one. I also checked a single .dat file corresponding to a later physical time instance, but Tecplot still reports the solution time as 0 s, which is not correct. As a quick check, I opened the .dat file in Notepad++ and noticed that the file header does not appear to contain any time information. I am not sure whether this is the source of the problem, but it seems related. Could you please advise whether the checkpoint files should contain physical time information after conversion to Tecplot format, or whether an additional option is required in FieldConvert to preserve/export this metadata? Any help would be greatly appreciated. Regards, Ishan PGR
IO_CheckSteps is being deprecated, better to use the filter going forward. MR2412 is likely to be merged soon. ________________________________ From: Ballester Ribo, Victor <v.ballester-ribo24@imperial.ac.uk> Sent: 24 April 2026 11:50 To: Xing, Jacques <j.xing@imperial.ac.uk>; Nande, Ishan A. <ian9@leicester.ac.uk>; nektar-users <nektar-users@imperial.ac.uk> Subject: Re: Time information in ".chk" --> ".dat" I am not using the filter for now, I am using the parameter command of IO_CheckSteps and it works fine. ________________________________ From: Xing, Jacques <j.xing@imperial.ac.uk> Sent: 24 April 2026 11:47 To: Nande, Ishan A. <ian9@leicester.ac.uk>; nektar-users <nektar-users@imperial.ac.uk> Subject: [Nektar-users] Re: Time information in ".chk" --> ".dat" Hi Ishan, It has been I while since I have used Tecplot, but I believe it is possible to assign a constant delta time to each .dat file. Cheers, Jacques ________________________________ From: Nande, Ishan A. <ian9@leicester.ac.uk> Sent: 24 April 2026 11:44 To: Xing, Jacques <j.xing@imperial.ac.uk>; nektar-users <nektar-users@imperial.ac.uk> Subject: RE: Time information in ".chk" --> ".dat" CAUTION: This message came from outside Imperial. Do not click links or open attachments unless you recognise the sender and were expecting this email. Hello Jacques, Thanks for the information. Yes, this seems to be the issue. I think for now, I will have to figure out a way to assign time from within Tecplot. Regards, Ishan PGR From: Xing, Jacques <j.xing@imperial.ac.uk> Sent: 24 April 2026 11:41 To: Nande, Ishan A. <ian9@leicester.ac.uk>; nektar-users <nektar-users@imperial.ac.uk> Subject: Re: Time information in ".chk" --> ".dat" ***CAUTION:*** This email was sent from an EXTERNAL source. Think before clicking links or opening attachments. Hi Ishan, I believe that your problem is being addressed in the following MR, which hopefully will be merged soon: https://gitlab.nektar.info/nektar/nektar/-/merge_requests/2412 Cheers, Jacques ________________________________ From: Nande, Ishan A. <ian9@leicester.ac.uk<mailto:ian9@leicester.ac.uk>> Sent: 24 April 2026 11:29 To: nektar-users <nektar-users@imperial.ac.uk<mailto:nektar-users@imperial.ac.uk>> Subject: [Nektar-users] Time information in ".chk" --> ".dat" CAUTION: This message came from outside Imperial. Do not click links or open attachments unless you recognise the sender and were expecting this email. Hello, I switched to Nektar++ v5.9.0 some time ago and I am currently having an issue with .chk files when using the Linearized Euler Equations solver. I am using the Checkpoint filter to save .chk files at the desired output frequency. I then convert these .chk files to Tecplot .dat format using the standard FieldConvert workflow. The conversion itself appears to work correctly, and the field data can be opened in Tecplot. However, when I load the resulting .dat files into Tecplot, I do not see any time information associated with them. As a result, I am unable to create animations, because the .dat files are not treated as sequential time instances; instead, each newly loaded file appears to replace the previously loaded one. I also checked a single .dat file corresponding to a later physical time instance, but Tecplot still reports the solution time as 0 s, which is not correct. As a quick check, I opened the .dat file in Notepad++ and noticed that the file header does not appear to contain any time information. I am not sure whether this is the source of the problem, but it seems related. Could you please advise whether the checkpoint files should contain physical time information after conversion to Tecplot format, or whether an additional option is required in FieldConvert to preserve/export this metadata? Any help would be greatly appreciated. Regards, Ishan PGR
participants (3)
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Ballester Ribo, Victor
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Nande, Ishan A.
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Xing, Jacques