Why is DZVP-MOLOPT-GTH much slower than DZVP-MOLOPT-SR-GTH in CP2K?

Donovan K

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May 16, 2026, 11:01:11 AMMay 16

to cp2k

Hi all,

I noticed that DZVP-MOLOPT-GTH is significantly slower than DZVP-MOLOPT-SR-GTH in my CP2K calculations, even though the setup is otherwise identical.

=========================================
CP2K| version string: CP2K version 2025.1
CP2K| source code revision number: git:9635df4
CP2K| cp2kflags: omp libint fftw3 libxc libgrpp pexsi elpa parallel scalapack c
CP2K| osma quip xsmm plumed2 spglib libdftd4 sirius libvori libbqb l
CP2K| libtorch libvdwxc hdf5 trexio
CP2K| is freely available from https://www.cp2k.org/
CP2K| Program compiled at Tue Jan 14 12:16:35 UTC 2025
CP2K| Program compiled on 7282285e16d1
CP2K| Program compiled for local
CP2K| Data directory path /opt/cp2k/data
CP2K| Input file name xtal-molopt-sr-9.inp

=========================================

The only difference is the presence of SR.

Example:

&KIND C
ELEMENT C
BASIS_SET DZVP-MOLOPT-GTH
POTENTIAL GTH-PBE-q4
&END KIND

vs

&KIND C
ELEMENT C
BASIS_SET DZVP-MOLOPT-SR-GTH
POTENTIAL GTH-PBE-q4
&END KIND

=================

&DFT
BASIS_SET_FILE_NAME BASIS_MOLOPT
POTENTIAL_FILE_NAME POTENTIAL

&QS
EPS_DEFAULT 1.0E-10
&END QS

&MGRID
CUTOFF 500
REL_CUTOFF 50
&END MGRID

&XC
&XC_FUNCTIONAL PBE
&END XC_FUNCTIONAL

&END XC

&SCF
SCF_GUESS ATOMIC
EPS_SCF 1.0E-7
MAX_SCF 300
&END SCF

&END DFT

=================

Computing time:

1. DZVP-MOLOPT-GTH
Step Update method Time Convergence Total energy Change
1 P_Mix/Diag. 13.3 1.37995875 -343.8583303534 -3.44E+02

1. DZVP-MOLOPT-SR-GTH
Step Update method Time Convergence Total energy Change
1 P_Mix/Diag. 0.40E+00 1.6 0.97935146 -341.1328952493 -3.41E+02

Is this expected behavior?
Does DZVP-MOLOPT-GTH introduce substantially more diffuse functions or a larger overlap matrix compared to the SR version?

Thanks!

xtal-molopt-sr-1.inp

xtal-molopt-1.inp

Marcella Iannuzzi

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May 17, 2026, 10:31:19 AMMay 17

to cp2k

Hi

The output reports the total number of atomic orbitals, i.e., the size of the matrix that is diagonalised. If the calculation is dominated by the diagonalization step, this size has a strong impact on the timings.

And yes, as you can check from the BASIS_MOLOPT library, the short range basis set is less diffuse

C DZVP-MOLOPT-GTH DZVP-MOLOPT-GTH-q4

1

2 0 2 7 2 2 1

6.132624767898 -0.105576563700 0.024850587600 0.035098108400 -0.056712999000 0.037469425800

2.625196064782 -0.174866621100 0.147440856000 0.114197930900 -0.076743951500 0.071047574800

1.045456957247 0.064464981400 -0.421418379200 0.215908137300 -0.528056757000 0.619330561200

0.478316330874 0.830447035300 0.823051336800 0.355929151000 0.394594045700 0.710730857000

0.178617414302 0.371911373800 0.184880712100 0.271541842000 0.721247475800 0.389148235000

0.075144725465 0.006174464000 -0.742086051600 0.056256557700 0.733902531700 0.346374124100

0.030286753006 0.008966477300 0.083382192000 0.004998059700 0.248172175500 -0.005142430900

C DZVP-MOLOPT-SR-GTH DZVP-MOLOPT-SR-GTH-q4

1

2 0 2 5 2 2 1

5.605330751705 0.111532881900 0.466507483200 -0.064868978500 -0.055475693400 0.029952774600

2.113016390533 0.153142194100 0.144113212800 -0.200470255700 -0.216165175200 0.070784458800

0.769911454810 -0.321396879400 0.029364880900 -0.413141730100 -0.436624272300 0.674601058600

0.348157086385 -0.610926421600 0.929470388400 -0.415337139200 0.784000698400 0.173652061800

0.128212254710 -0.133990862800 1.066914331200 -0.288527673600 0.987908135000 1.036317024700

Regards

Marcella

Jürg Hutter

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May 18, 2026, 4:42:10 AMMay 18

to cp...@googlegroups.com

Hi
as a rule of thumb, the costs for integrals goes with

(1/a)^3/2. where a is the value of the most diffuse exponent in the basis.

For hybrid functionals this becomes (1/a)^3, making it clear why the ADMM method is so much faster.

regards
JH

________________________________________
From: cp...@googlegroups.com <cp...@googlegroups.com> on behalf of Marcella Iannuzzi <marci...@gmail.com>
Sent: Sunday, May 17, 2026 4:31 PM
To: cp2k
Subject: [CP2K:22236] Re: Why is DZVP-MOLOPT-GTH much slower than DZVP-MOLOPT-SR-GTH in CP2K?

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