Describe the bug
Currently in LTS or v3.11.0.beta1, users can specify the dft_functional parameter as the SCAN-L functional to implement structural self-consistent iterations and single-point energy calculations. However, there exists a critical logical defect when this interface invokes the Libxc library for underlying physical parameter calculation. The software fails to accurately compute and transmit the Laplacian term, and instead adopts the sigma variable for approximate substitution. Such an approximation deviates from the rigorous theoretical definition and original derivation of the SCAN-L functional, thereby inducing systematic errors in key physical quantities including electronic structures and total energy, and ultimately leading to inaccurate computational results. Following the development standards of mainstream first-principles simulation codes, it is expected that ABACUS can strictly and completely realize the standard calculation of the Laplacian-related terms in the SCAN-L functional by referring to the mature implementation scheme of VASP. Alternatively, similar to the fault-tolerant design of QE, the program should feed back explicit error prompts to indicate functional incompatibility when full calculation support is unavailable, rather than outputting misleading erroneous data for subsequent research. Furthermore, the inherent Laplacian term of the SCAN-L functional is accompanied by obvious numerical instability, which serves as a key technical issue requiring special attention in code implementation and algorithm optimization. In addition, the calculation modules of atomic force and system stress should be repaired synchronously in line with the optimized functional logic. Corresponding modifications are required to ensure that the revised SCAN-L functional implementation can pass rigorous energy difference tests and meet the accuracy and convergence criteria of systematic first-principles calculations.
Expected behavior
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To Reproduce
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Environment
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Additional Context
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Task list for Issue attackers (only for developers)
Describe the bug
Currently in LTS or v3.11.0.beta1, users can specify the dft_functional parameter as the SCAN-L functional to implement structural self-consistent iterations and single-point energy calculations. However, there exists a critical logical defect when this interface invokes the Libxc library for underlying physical parameter calculation. The software fails to accurately compute and transmit the Laplacian term, and instead adopts the sigma variable for approximate substitution. Such an approximation deviates from the rigorous theoretical definition and original derivation of the SCAN-L functional, thereby inducing systematic errors in key physical quantities including electronic structures and total energy, and ultimately leading to inaccurate computational results. Following the development standards of mainstream first-principles simulation codes, it is expected that ABACUS can strictly and completely realize the standard calculation of the Laplacian-related terms in the SCAN-L functional by referring to the mature implementation scheme of VASP. Alternatively, similar to the fault-tolerant design of QE, the program should feed back explicit error prompts to indicate functional incompatibility when full calculation support is unavailable, rather than outputting misleading erroneous data for subsequent research. Furthermore, the inherent Laplacian term of the SCAN-L functional is accompanied by obvious numerical instability, which serves as a key technical issue requiring special attention in code implementation and algorithm optimization. In addition, the calculation modules of atomic force and system stress should be repaired synchronously in line with the optimized functional logic. Corresponding modifications are required to ensure that the revised SCAN-L functional implementation can pass rigorous energy difference tests and meet the accuracy and convergence criteria of systematic first-principles calculations.
Expected behavior
No response
To Reproduce
No response
Environment
No response
Additional Context
No response
Task list for Issue attackers (only for developers)