CPMD - Revision history

import>Jss43: /* Local Modifications */

2007-01-31T12:03:29Z

Local Modifications

← Older revision		Revision as of 12:03, 31 January 2007
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	* &QMC and &SYM sections to the input file.		* &QMC and &SYM sections to the input file.
	* Calculate symmetry of the states.		* Calculate symmetry of the states.
	* Compute integrals of the type <math><i\|v_{xc}\|j></math> and <math><ij\|kl></math>.		* Compute integrals of the type <math>\langle i\|v_{xc}\|j \rangle</math> and <math>\langle ij\|kl \rangle</math>.
	* Integration with NECI code (mainly qmc* subroutines, plus antisymint.F). NECI code resides in the NECI subdirectory.		* Integration with NECI code (mainly qmc* subroutines, plus antisymint.F). NECI code resides in the NECI subdirectory.

import>Jss43 at 14:22, 14 December 2006

2006-12-14T14:22:07Z

← Older revision		Revision as of 14:22, 14 December 2006
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	Current work focuses on the implementation of the above with k-point sampling.		Current work focuses on the implementation of the above with k-point sampling.

	--[[User:jss43\|james]] 14:19, 14 December 2006 (GMT)		--[[User:jss43\|james]] 14:22, 14 December 2006 (GMT)

	= Input file options =		= Input file options =
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	Many additional options are now available in the local code. These are covered in the LOCAL_MODS file in the repository and in [[CPMDInput]].		Many additional options are now available in the local code. These are covered in the LOCAL_MODS file in the repository and in [[CPMDInput]].

	--[[User:jss43\|james]] 14:19, 14 December 2006 (GMT)		--[[User:jss43\|james]] 14:22, 14 December 2006 (GMT)

	= Technical tricks =		= Technical tricks =

import>Jss43 at 14:19, 14 December 2006

2006-12-14T14:19:24Z

← Older revision		Revision as of 14:19, 14 December 2006
Line 8:		Line 8:
	* Integration with NECI code (mainly qmc* subroutines, plus antisymint.F). NECI code resides in the NECI subdirectory.		* Integration with NECI code (mainly qmc* subroutines, plus antisymint.F). NECI code resides in the NECI subdirectory.

			Current work focuses on the implementation of the above with k-point sampling.
	= Input file options =

			--[[User:jss43\|james]] 14:19, 14 December 2006 (GMT)
⚫	Many additional options are now available in the local code. These are covered in the LOCAL_MODS file in the repository and [[CPMDInput]].
	The following are in addition to the options given in the manual for CPMD v3.11.1.

	== ~~&CPMD~~ ~~section~~ ==		= Input file options =

		⚫	Many additional options are now available in the local code. These are covered in the LOCAL_MODS file in the repository and in [[CPMDInput]].
	* QMC
	Run NECI code using Kohn-Sham orbitals generated by CPMD. Need to perform a wavefunction optimization calclulation first---requires the RESTART file and the QMC input file (default filename: inp.)

			--[[User:jss43\|james]] 14:19, 14 December 2006 (GMT)
	* 4-INDEX INTEGRALS
	Compute the integrals <math><i\|v_{xc}\|j></math> and <math><ij\|kl></math> if not doing a QMC run. (Calculated on the fly or as an initialisation for QMC jobs.)

		⚫	= Technical tricks =
	* RESTART SYMMETRY 2-INDEX 4-INDEX
	Read in the symmetry, <math>v_{xc}</math> and 4-index integrals respectively, from the files SYMMETRY, 2INDEXINT and 4INDEXINT.

			Please add!
	== &QMC section ==

	Specify options relevant to a QMC job.

	* INPUT FILE <filename>
	QMC input filename.

	* MEMORY ALLOCATE <Memory in MB>
	Specify the size of memory block to use to store wavefunctions in real space in MB. Default is 500MB.

	* INTEGRALS FAST
	Compute the four-index integrals quicker using a coarser mesh (currently not working---don't use).

	* INTEGRALS PRINT
	Print out the 'non-special' <math><ab\|cd></math> integrals to the file abcdint.

	== &SYM section ==

	Options for symmetry code.

	* CALC SYM [ALL,OFF]
	ALL: Calculate characters due to rotational symmetry for all operations rather than by classes (default). If the system is non-symmorphic, then characters are found for each operation automatically.

	OFF: Turns symmetry off (by setting each state to be totally symmetric).

	* INTERPOLATE <NSHELLS>
	A symmetry operation may not necessarily move us from one mesh point to another. A Lagrange interpolation process is used to find the wavefunction by using NSHELLS (default 1) of boxes around the point (i.e. an interpolation of order 2*NSHELLS-1). The scaling is not so nice, but you shouldn't really need to ever go above 2 (and 1 is almost always good enough).

	* INT STEP <SYMINTSTEP>
	The calculation of characters by <psi\|R\|psi> over the real space mesh is fairly costly. Integrating using a step size of SYMINTSTEP (default 1) can speed things up significantly for large high-symmetry systems. Integrating using every other point (INT STEP 2) is a good value---there appears to be little loss in accuracy. SYMINTSTEP=4 is less good (i.e. really shouldn't be used). A check is made the the specified value is consumerate with the real space mesh (if it isn't, then SYMINTSTEP=1 is set).

	* TRANS SYM OFF
	Turn off translational symmetry for supercells. (Not applicable if space group symmetry is used.)

	* SPACE GROUP [OFF]
	Use rotational and translational symmetry (if applicable) separately, rather than all the symmetry operations of the space group.

	* DEGEN TOL <DEGEN TOL>
	Specify the tolerance for two states to be considered degenerate. Default is 1.d-6.

	== &QMC section ==

	Specify options relevant to a QMC job.

	* INPUT FILE <filename>
	QMC input filename.

	* MEMORY ALLOCATE <Memory in MB>
	Specify the size of memory block to use to store wavefunctions in real space in MB. Default is 500MB.

	* INTEGRALS FAST
	Compute the four-index integrals quicker using a coarser mesh (currently not working---don't use).

	* INTEGRALS PRINT
	Print out the ''non-special'' <math><ab\|cd></math> integrals to the file abcdint.

	&SYM section:
	Options for symmetry code.

	* CALC SYM [ALL,OFF]
	ALL: Calculate characters due to rotational symmetry for all operations rather than by classes (default). If the system is non-symmorphic, then characters are found for each operation automatically.

	OFF: Turns symmetry off (by setting each state to be totally symmetric).

⚫	= Technical tricks =

import>Jss43 at 14:16, 14 December 2006

2006-12-14T14:16:06Z

← Older revision		Revision as of 14:16, 14 December 2006
Line 10:		Line 10:
	= Input file options =		= Input file options =

			Many additional options are now available in the local code. These are covered in the LOCAL_MODS file in the repository and [[CPMDInput]].
	The following are in addition to the options given in the manual for CPMD v3.11.1.		The following are in addition to the options given in the manual for CPMD v3.11.1.

import>Jss43 at 14:13, 14 December 2006

2006-12-14T14:13:51Z

New page

= Local Modifications =

Local modifications to CPMD:

* &QMC and &SYM sections to the input file.
* Calculate symmetry of the states.
* Compute integrals of the type <math><i|v_{xc}|j></math> and <math><ij|kl></math>.
* Integration with NECI code (mainly qmc* subroutines, plus antisymint.F). NECI code resides in the NECI subdirectory.

= Input file options =

The following are in addition to the options given in the manual for CPMD v3.11.1.

== &CPMD section ==

* QMC
Run NECI code using Kohn-Sham orbitals generated by CPMD. Need to perform a wavefunction optimization calclulation first---requires the RESTART file and the QMC input file (default filename: inp.)

* 4-INDEX INTEGRALS
Compute the integrals <math><i|v_{xc}|j></math> and <math><ij|kl></math> if not doing a QMC run. (Calculated on the fly or as an initialisation for QMC jobs.)

* RESTART SYMMETRY 2-INDEX 4-INDEX
Read in the symmetry, <math>v_{xc}</math> and 4-index integrals respectively, from the files SYMMETRY, 2INDEXINT and 4INDEXINT.

== &QMC section ==

Specify options relevant to a QMC job.

* INPUT FILE <filename>
QMC input filename.

* MEMORY ALLOCATE <Memory in MB>
Specify the size of memory block to use to store wavefunctions in real space in MB. Default is 500MB.

* INTEGRALS FAST
Compute the four-index integrals quicker using a coarser mesh (currently not working---don't use).

* INTEGRALS PRINT
Print out the 'non-special' <math><ab|cd></math> integrals to the file abcdint.

== &SYM section ==

Options for symmetry code.

* CALC SYM [ALL,OFF]
ALL: Calculate characters due to rotational symmetry for all operations rather than by classes (default). If the system is non-symmorphic, then characters are found for each operation automatically.

OFF: Turns symmetry off (by setting each state to be totally symmetric).

* INTERPOLATE <NSHELLS>
A symmetry operation may not necessarily move us from one mesh point to another. A Lagrange interpolation process is used to find the wavefunction by using NSHELLS (default 1) of boxes around the point (i.e. an interpolation of order 2*NSHELLS-1). The scaling is not so nice, but you shouldn't really need to ever go above 2 (and 1 is almost always good enough).

* INT STEP <SYMINTSTEP>
The calculation of characters by <psi|R|psi> over the real space mesh is fairly costly. Integrating using a step size of SYMINTSTEP (default 1) can speed things up significantly for large high-symmetry systems. Integrating using every other point (INT STEP 2) is a good value---there appears to be little loss in accuracy. SYMINTSTEP=4 is less good (i.e. really shouldn't be used). A check is made the the specified value is consumerate with the real space mesh (if it isn't, then SYMINTSTEP=1 is set).

* TRANS SYM OFF
Turn off translational symmetry for supercells. (Not applicable if space group symmetry is used.)

* SPACE GROUP [OFF]
Use rotational and translational symmetry (if applicable) separately, rather than all the symmetry operations of the space group.

* DEGEN TOL <DEGEN TOL>
Specify the tolerance for two states to be considered degenerate. Default is 1.d-6.

== &QMC section ==

Specify options relevant to a QMC job.

* INPUT FILE <filename>
QMC input filename.

* MEMORY ALLOCATE <Memory in MB>
Specify the size of memory block to use to store wavefunctions in real space in MB. Default is 500MB.

* INTEGRALS FAST
Compute the four-index integrals quicker using a coarser mesh (currently not working---don't use).

* INTEGRALS PRINT
Print out the ''non-special'' <math><ab|cd></math> integrals to the file abcdint.

&SYM section:
Options for symmetry code.

* CALC SYM [ALL,OFF]
ALL: Calculate characters due to rotational symmetry for all operations rather than by classes (default). If the system is non-symmorphic, then characters are found for each operation automatically.

OFF: Turns symmetry off (by setting each state to be totally symmetric).

= Technical tricks =