Back to the main page of this manual  Input reference of CP2K version 2022.1 (Development Version) 
CP2K_INPUT /
FORCE_EVAL /
DFT /
TDDFPT /
XC /
WF_CORRELATION /
LOW_SCALING
&LOW_SCALING {Logical} 

Activates cubicscaling RPA, GW and LaplaceSOSMP2 calculations. [Edit on GitHub]  
This keyword cannot be repeated and it expects precisely one logical.  
The lone keyword behaves as a switch to
.TRUE. 

Default value:
.FALSE. 
DO_EXTRAPOLATE_KPOINTS {Logical} 

If true, use a larger kmesh to extrapolate the kpoint integration of W. For example, in 2D, when using KPOINTS 4 4 1, an additional 6x6x1 mesh will be used to extrapolate the kpoint integration of W with N_k^0.5, where Nk is the number of kpoints. [Edit on GitHub]  
This keyword cannot be repeated and it expects precisely one logical.  
The lone keyword behaves as a switch to
.TRUE. 

Default value:
.TRUE. 
DO_KPOINTS {Logical} 

Besides in DFT, this keyword has to be switched on if one wants to do kpoints in. cubic RPA. [Edit on GitHub]  
This keyword cannot be repeated and it expects precisely one logical.  
The lone keyword behaves as a switch to
.TRUE. 

Default value:
.FALSE. 
EPS_EIGVAL_S {Real} 

Parameter to reduce the expansion coefficients in RI for periodic GW. Removes all eigenvectors and eigenvalues of S_PQ(k) that are smaller than EPS_EIGVAL_S. [Edit on GitHub]  
This keyword cannot be repeated and it expects precisely one real.  
Default value:
0.00000000E+000 
EPS_FILTER {Real} 

Determines a threshold for the DBCSR based multiply.Normally, this EPS_FILTER determines accuracy and timing of lowscaling RPA and GW calculations. [Edit on GitHub]  
This keyword cannot be repeated and it expects precisely one real.  
Default value:
1.00000000E009 
EPS_FILTER_FACTOR {Real} 

Multiply EPS_FILTER with this factor to determine filter epsilon for DBCSR based multiply P(it)=(Mocc(it))^T*Mvirt(it) Default should be kept. [Edit on GitHub]  
This keyword cannot be repeated and it expects precisely one real.  
Default value:
1.00000000E+001 
EPS_STORAGE_SCALING {Real} 

Scaling factor to scale EPS_FILTER. Storage threshold for compression will be EPS_FILTER*EPS_STORAGE_SCALING. [Edit on GitHub]  
This keyword cannot be repeated and it expects precisely one real.  
Default value:
1.00000000E003 

Alias names for this keyword: EPS_STORAGE 
EXPONENT_TAILORED_WEIGHTS {Real} 

Gives the exponent of exactly integrated function in case 'KPOINT_WEIGHTS_W TAILORED' is chosen. [Edit on GitHub]  
This keyword cannot be repeated and it expects precisely one real.  
Default value:
2.00000000E+000 
GREENS_FUNCTION {Keyword} 

Decides which scheme is used for the periodic Green's function (only relevant for periodic GW calculations).Both schemes are exact in the limit of large unit cells. [Edit on GitHub]  
This keyword cannot be repeated and it expects precisely one keyword.  
Default value:
GAMMA 

List of valid keywords:

KEEP_QUADRATURE {Logical} 

Keep the Laplace quadrature defined at the first energy evaluations throughout the run. Allows to have consistent force evaluations. [Edit on GitHub]  
This keyword cannot be repeated and it expects precisely one logical.  
The lone keyword behaves as a switch to
.TRUE. 

Default value:
.TRUE. 

Alias names for this keyword: KEEP_WEIGHTS, KEEP_QUAD, KEEP_WEIGHT 
KPOINTS {Integer} {Integer} {Integer} 

Keyword activates periodic, lowscaling GW calculations (&LOW_SCALING section also needed). For periodic calculations, kpoints are used for the density response, the Coulomb interaction and the screened Coulomb interaction. For 2d periodic systems, e.g. xz periodicity, please also specify KPOINTS, e.g. N_x 1 N_z. [Edit on GitHub]  
This keyword cannot be repeated and it expects precisely 3 integers.  
Default values:
0 0 0 
KPOINT_WEIGHTS_W {Keyword} 

For kpoints in lowscaling GW, a MonkhorstPack mesh is used. The screened Coulomb interaction W(k) needs special care near the Gamma point (e.g. in 3d, W(k) diverges at the Gamma point with W(k) ~ k^alpha). KPOINT_WEIGHTS_W decides how the weights of the MonkhorstPack mesh are chosen to compute W(R) = int_BZ W(k) exp(ikR) dk (BZ=Brllouin zone). [Edit on GitHub]  
This keyword cannot be repeated and it expects precisely one keyword.  
Default value:
UNIFORM 

List of valid keywords:

K_MESH_G_FACTOR {Integer} 

The kmesh for the Green's function can be chosen to be larger than the kmesh for W (without much higher computational cost). The factor given here multiplies the mesh for W to obtainthe kmesh for G. Example: factor 4, kmesh for W: 4x4x1 > kmesh for G: 16x16x1 (zdir. is nonperiodic). [Edit on GitHub]  
This keyword cannot be repeated and it expects precisely one integer.  
Default value:
1 
MAKE_CHI_POS_DEFINITE {Logical} 

If true, makes eigenvalue decomposition of chi(iw,k) and removes negative eigenvalues. May increase computational cost significantly. Only recommended to try in case Cholesky decomposition of epsilon(iw,k) fails. [Edit on GitHub]  
This keyword cannot be repeated and it expects precisely one logical.  
The lone keyword behaves as a switch to
.TRUE. 

Default value:
.TRUE. 
MEMORY_CUT {Integer} 

Reduces memory for sparse tensor contractions by this factor. A high value leads to some loss of performance. This memory reduction factor applies to storage of the tensors 'M occ' / 'M virt' but does not reduce storage of '3c ints'. [Edit on GitHub]  
This keyword cannot be repeated and it expects precisely one integer.  
Default value:
5 
MEMORY_INFO {Logical} 

Decide whether to print memory info on the sparse matrices. [Edit on GitHub]  
This keyword cannot be repeated and it expects precisely one logical.  
The lone keyword behaves as a switch to
.TRUE. 

Default value:
.FALSE. 
MIN_BLOCK_SIZE {Integer} 

Minimum tensor block size. Adjusting this value may have minor effect on performance but default should be good enough. [Edit on GitHub]  
This keyword cannot be repeated and it expects precisely one integer.  
Default value:
5 
MIN_BLOCK_SIZE_MO {Integer} 

Tensor block size for MOs. Only relevant for GW calculations. The memory consumption of GW scales as O(MIN_BLOCK_SIZE_MO). It is recommended to set this parameter to a smaller number if GW runs out of memory. Otherwise the default should not be changed. [Edit on GitHub]  
This keyword cannot be repeated and it expects precisely one integer.  
Default value:
64 
REGULARIZATION_RI {Real} 

Parameter to reduce the expansion coefficients in RI for periodic GW. Larger parameter means smaller expansion coefficients that leads to a more stable calculation at the price of a slightly worse RI approximation. In case the parameter 0.0 is chosen, ordinary RI is used. [Edit on GitHub]  
This keyword cannot be repeated and it expects precisely one real.  
Default value:
0.00000000E+000 
REL_CUTOFFS_CHI_W {Real} {Real} 

For periodic calculations, the irreducible density reponse chi^0(r,r') and the screened Coulomb interaction W(r,r') is truncated in real space. No truncation of chi^0(r,r') and W(r,r') for rr' < cutoff_1*(smallest lattice vector length), chi^0(r,r') is set to zero for rr' > cutoff_2*(smallest lattice vector length). Smooth transition in between. For cutoff_1 = 0.5, and cutoff_2 = 0.5, we have the minimum image convention (that is also default). [Edit on GitHub]  
This keyword cannot be repeated and it expects precisely 2 reals.  
Default values:
5.00000000E001 5.00000000E001 
REL_CUTOFF_TRUNC_COULOMB_RI_X {Real} 

Only active in case TRUNC_COULOMB_RI_X = True. Normally, relative cutoff = 0.5 is good choice; still needs to be evaluated for RI schemes. [Edit on GitHub]  
This keyword cannot be repeated and it expects precisely one real.  
Default value:
5.00000000E001 
TRUNC_COULOMB_RI_X {Logical} 

If true, use the truncated Coulomb operator for the exchangeselfenergy in periodic GW. [Edit on GitHub]  
This keyword cannot be repeated and it expects precisely one logical.  
The lone keyword behaves as a switch to
.TRUE. 

Default value:
.TRUE. 
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