COMBINE_COLVAR

Allows the possibility to combine several COLVARs into one COLVAR with a generic function. A functional form is specified. Mathematical Operators recognized are +, -, *, /, ^ or alternatively **, whereas symbols for brackets must be (). The function parser recognizes the Fortran 90 intrinsic functions abs, min, max, exp, log10, log, sqrt, sinh, cosh, tanh, sin, cos, tan, asin, acos, atan2, atan, erf, erfc. Parsing for intrinsic functions is not case sensitive. [Edit on GitHub]

Subsections

• COLVAR

Keywords

• DX

• ERROR_LIMIT

• FUNCTION

• PARAMETERS

• VALUES

• VARIABLES

Keyword descriptions

DX

Type: real
Default: 1.00000000E-001 [bohr]
Usage: DX

Description: Parameter used for computing the derivative of the combination of COLVARs with the Ridders’ method.

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ERROR_LIMIT

Type: real
Default: 1.00000000E-012
Usage: ERROR_LIMIT

Description: Checks that the error in computing the derivative is not larger than the value set; in case error is larger a warning message is printed.

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FUNCTION

Type: string
Usage: FUNCTION SQRT(CV1^2+CV2^2)

Description: Specifies the function used to combine different COLVARs into one.

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PARAMETERS

Type: string[ ]
Repeatable: yes
Usage: PARAMETERS a b D

Description: Defines the parameters of the functional form

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VALUES

Type: real[ ]
Default: [internal_cp2k]
Repeatable: yes
Usage: VALUES

Description: Defines the values of parameter of the functional form

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VARIABLES

Type: string[ ]
Usage: VARIABLES CV1 CV2 CV3

Description: Specifies the name of the variable that parametrises the FUNCTION defining how COLVARS should be combined. The matching follows the same order of the COLVARS definition in the input file.

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