Update README.md

Author: matthewkuner

README.md

@@ -38,7 +38,7 @@ Rationale
 | ---- | ---- |
 | ADDGRID | ADDGRID must be set to False. MP uses ADDGRID = False, as the VASP manual states “please do not use this tag [ADDGRID] as default in all your calculations!”. ADDGRID can affect the outputted forces, hence all calculations are thus required to have ADDGRID = False for compatibility. |
 | AEXX / AMGGAX / AMGGAC / AGGAX / ALDAC / ALDAX | These parameters should be the VASP defaults unless otherwise specified in a given MP input set, as changing them is effectively a change to the level of theory. |
-| ALGO / IALGO | ALGO must be one of: "Normal", "Conjugate", "All", "Fast","Exact". (This corresponds to an IALGO of 38, 58, 58, 68, 90, respectively). |
+| ALGO / IALGO | ALGO must be one of: "Normal", "Conjugate", "All", "Fast", "Exact". (This corresponds to an IALGO of 38, 58, 58, 68, 90, respectively). |
 | DEPER / EBREAK / WEIMIN | DEPER, EBREAK, and WEIMIN should not be changed according to the VASP wiki, hence MP requires them to remain as their default values. |
 | EDIFF | EDIFF must be equal to or greater than the value in the relevant MP input set. This will ensure compatibility between results with those in the MP Database. |
 | EDIFFG | Should be the same or better than in the relevant MP input set. For MP input sets with an energy-based cutoff, the calculation must have an energy change between the last two steps be less in magnitude than the specified EDIFFG (so even if your calculation uses force-based convergence, the energy must converge within the MP input set’s specification). The same logic applies to MP input sets with force-based EDIFFG settings. |
@@ -56,7 +56,7 @@ Rationale
 | IDIPOL | IDIPOL must be set to 0 (the VASP default). |
 | IMAGES | IMAGES must be set to 0 to match MP calculations. |
 | INIWAV | INIWAV must be set as the VASP default of 1 to be consistent with MP calculations. |
-| ISPIN | All values of ISPIN are allowed, though it should be noted that virtuall all MP calculations permit spin symmetry breaking, and have ferromagnetic, antiferrogmanetic, or nonmagnetic ordering. |
+| ISPIN | All values of ISPIN are allowed, though it should be noted that virtually all MP calculations permit spin symmetry breaking, and have ferromagnetic, antiferrogmanetic, or nonmagnetic ordering. |
 | ISMEAR | The appropriate ISMEAR depends on the bandgap of the material (which cannot be known a priori). As per the VASP manual: for metals (bandgap = 0), any ISMEAR value in [0, 1, 2] is acceptable. For nonmetals (bandgap > 0), any ISMEAR value in [-5, 0] is acceptable. Hence, for those who are performing normal relaxations/static calculations and want to ensure their calculations are MP-compatible, we recommend setting ISMEAR to 0. |
 | ISIF | MP allows any ISIF $\geq 2$. This value is restricted as such simply because all ISIF values $\geq 2$ output the complete stress tensor. |
 | ISYM | ISYM must be one of -1, 0, 1, 2, except for when the relevant MP input set uses a hybrid functional, in which case ISYM=3 is also allowed. |
@@ -66,7 +66,7 @@ Rationale
 | KGAMMA | KGAMMA must be set to True (the VASP default). This is only relevant when no KPOINTS file is used. |
 | KSPACING / KPOINTS | The KSPACING parameter or KPOINTS file must correspond with at least 0.9 times **the number of KPOINTS in the non-symmetry-reduced Brillouin zone specified by the relevant MP input set** (i.e., not the number of points in the irreducible wedge of the first Brillouin zone). Hence, either method of specifying the KPOINTS can be chosen. This ensures that a calculation uses a comparable number of kpoints to MP. |
 | Kpoint mesh type (for KPOINTS) | The type of Kpoint mesh must be valid for the symmetry of the crystal structure in the calculation. For example, for a hexagonal closed packed structure, one must use a $\Gamma$-centered mesh. All Kpoints generated using Pymatgen *should* be valid. |
-| LASPH | LASPH must be set to True (this is <u>*not*</u> the VASP default). |
+| LASPH | LASPH must be set to True (this is **<u>*not*</u>** the VASP default). |
 | LCALCEPS | LCALCEPS must be set to False (the VASP default). |
 | LBERRY | LBERRY must be set to False (the VASP default). |
 | LCALCPOL | LCALCPOL  must be set to False (the VASP default). |
@@ -88,26 +88,26 @@ Rationale
 | LNONCOLLINEAR / LSORBIT | Both must be set to False (VASP defaults) |
 | LOCPROJ | LOCPROJ must be set to None (the VASP default). |
 | LOPTICS | LOPTICS must be set to False (the VASP default), unless explicitly specified by the relevant MP input set. |
-| LORBIT | LORBIT must <u>*not*</u> be None if the user also sets ISPIN=2, otherwise all values of LORBIT are acceptable. This is due to magnetization values not being output when ISPIN=2 and LORBIT = None are set together. |
+| LORBIT | LORBIT must **<u>*not*</u>** be None if the user also sets ISPIN=2, otherwise all values of LORBIT are acceptable. This is due to magnetization values not being output when ISPIN=2 and LORBIT = None are set together. |
 | LREAL | If the LREAL in the relevant MP input set is “Auto”, then the user must be one of: "Auto", False. Otherwise, if the LREAL in the relevant MP input set is False, then the user must use False. |
 | LRPA | LRPA must be set to False (the VASP default). MP does not currently support random phase approximation (RPA) calculations. |
 | LSPECTRAL | LSPECTRAL must be set to False (the VASP default for most calculations). |
 | LSUBROT | LSUBROT must be set to False (the VASP default). |
 | MAGMOM | While any initial magnetic moments are allowed, the final total magnetic moment for any given atom must be less than 5 $\mu_B$ (Bohr magnetons) (except for elements Gd and Eu, which must be less than 10 $\mu_B$). This simply serves as a filter for erroneous data. |
 | ML_LMFF | ML_LMFF must be set to False (the VASP default). |
-| NG{X,Y,Z} | The values for NGX/NGY/NGZ must be at least 0.9 times <the default value for the respective parameter generated by VASP>. If the user simply does not specify these parameters, the calculation should be compatible with MP data. |
-| NGF{X,Y,Z} | The values for NGFX/NGFY/NGFZ must be at least 0.9 times <the default value for the respective parameter generated by VASP>. If the user simply does not specify these parameters, the calculation should be compatible with MP data. |
+| NG{X,Y,Z} | The values for NGX/NGY/NGZ must be at least 0.9 times the default value for the respective parameter generated by VASP. If the user simply does not specify these parameters, the calculation should be compatible with MP data. |
+| NGF{X,Y,Z} | The values for NGFX/NGFY/NGFZ must be at least 0.9 times the default value for the respective parameter generated by VASP. If the user simply does not specify these parameters, the calculation should be compatible with MP data. |
 | NLSPLINE | NLSPLINE should be set to False (the VASP default), unless explicitly specified by the relevant MP input set. |
-| NBANDS | NBANDS must be greater than the value $\mathrm{ceil}(\mathrm{NELECT}/2) + 1 $(minimum allowable number of bands to avoid degeneracy) and less than 4 times <minimum allowable number of bands to avoid degeneracy>. For high-throughput calculations, it is generally recommended to not set this parameter directly. See https://github.com/materialsproject/custodian/issues/224 for more information. |
-| NELECT | NELECT must not be changed from the default value VASP would use for the particular structure and pseudopotentials calculated. The easiest way to ensure this is to simply not specify NELECT in the INCAR file. |
+| NBANDS | NBANDS must be greater than the value $\mathrm{ceil}(\mathrm{NELECT}/2) + 1 $(minimum allowable number of bands to avoid degeneracy) and less than 4 times (minimum allowable number of bands to avoid degeneracy). For high-throughput calculations, it is generally recommended to not set this parameter directly. See https://github.com/materialsproject/custodian/issues/224 for more information. |
+| NELECT | NELECT must not be changed from the default value VASP would use for the particular structure and pseudopotentials calculated. The easiest way to ensure that NELECT is compliant with MP data is to simply not specify NELECT in the INCAR file. |
 | NWRITE | NWRITE must be set to be $\geq 2$ (the VASP default is 2). |
 | POTIM | POTIM $\leq 5$. We suggest not setting POTIM in the INCAR file, and rather allowing VASP to set it to the default value of 0.5. |
 | PSTRESS | PSTRESS must be set to exactly 0.0 (the VASP default). |
-| PREC | PREC must be one of: "High", "Accurate" |
+| PREC | PREC must be one of: "High", "Accurate". |
 | ROPT | ROPT should be set to be less than or equal to the default ROPT value (which is set based on the PREC tag). Hence, it is recommended to not set the ROPT tag in the INCAR file. |
 | RWIGS | RWIGS should not be set in the INCAR file. |
-| SCALEE | SCALEE should not be set. |
-| SYMPREC | SYMPREC must be less than or equal to 1e-3 (as this is the maximum value that the Custodian package will set SYMPREC as of March 2024). |
+| SCALEE | SCALEE should not be set in the INCAR file. |
+| SYMPREC | SYMPREC must be less than or equal to 1e-3 (as this is the maximum value that the Custodian package will set SYMPREC as of March 2024). For general use, we recommend leaving SYMPREC as the default generated by your desired MP input set. |
 | SIGMA | There are several rules for setting SIGMA:  <ol> <li> SIGMA  must be $\leq 0.05$ for non-metals (bandgap $>  0$). </li> <li> SIGMA must be $\leq 0.2$ for a metal (bandgap = 0). </li> <li> For metals, the SIGMA value must be small enough that the entropy term in the energy is $\leq$ 1 meV/atom (as suggested by the VASP manual). </li> </ol> |
 | VCA | MP data does not include Virtual Crystal Approximation (VCA) calculations from VASP. As such, this parameter should not be set. |
 | VASP version | The following versions of VASP are allowed: 5.4.4 or $>$ 6.0.0. For example, versions $<=$ 5.4.3 are not allowed, whereas version 6.3.1 is allowed. |