SPIN_TYP inconsistency with Cyclix (DCH) boundary conditions

[ktksrv]

I encountered an inconsistency in SPIN_TYP behavior when using SPARC-Cyclix (DCH boundary conditions) with SOC.

• With SPIN_TYP = 0, the calculation runs successfully.

• With SPIN_TYP = 1, the code throws:

  “collinear spin cannot be used with SOC, please use non-collinear spin (SPIN_TYP = 2)”

• Switching to SPIN_TYP = 2 results in:

  “SQ, Hybrid functional, SCAN, SQ3, CS, OFDFT and SQ are not supported in this version of non-collinear implementation.”

However, I am explicitly using:

EXCHANGE_CORRELATION = GGA_PBE

which should not fall under the unsupported categories listed above.
Is this expected behavior, or a bug?

[phanish-suryanarayana]

To confirm, you set SPIN_TYP = 2 and EXCHANGE_CORRELATION = GGA_PBE?

[ktksrv]

Yes, I set SPIN_TYP = 2 and EXCHANGE_CORRELATION = GGA_PBE in the Cyclix (DCH), and I still get the following error:

“SQ, Hybrid functional, SCAN, SQ3, CS, OFDFT and SQ are not supported in this version of non-collinear implementation.”

[ktksrv]

Hi, just checking in on this. Happy to provide any additional details if helpful. Thanks so much for your time!

[sayanbhowmik]

Hi!
The non-collinear spin feature with SOC in cyclix has not been well tested within the code so it was disabled. However, if you change the if condition to exclude the cyclix flag in line:
https://github.com/SPARC-X/SPARC/blob/a2ecc61b19090f9c99dd0f5eedb18cb588d58884/src/initialization.c#L2969
the code should work.

Currently:
if (pSPARC->sqAmbientFlag || pSPARC->sqHighTFlag || pSPARC->usefock || pSPARC->ixc[2] || pSPARC->CyclixFlag || pSPARC->OFDFTFlag)
Change to:
if (pSPARC->sqAmbientFlag || pSPARC->sqHighTFlag || pSPARC->usefock || pSPARC->ixc[2] || pSPARC->OFDFTFlag)

Let us know if additional issues crop up. Thanks for your patience.