Action: DUMPDERIVATIVES

Module	generic
Description	Usage
Dump the derivatives with respect to the input parameters for scalar values (generally CVs, functions or biases).
This action outputs data to a file. You can read more about how PLUMED manages output files here

Input

The arguments that serve as the input for this action are specified using one or more of the keywords in the following table.

Further details and examples

Dump the derivatives with respect to the input parameters for scalar values (generally CVs, functions or biases).

You can use this command to output the derivatives of a scalar with respect to whatever input parameters are used to calculate that scalar. For example, the following input instructs plumed to write a file called deriv that contains both the analytical and numerical derivatives of the distance between atoms 1 and 2.

Click on the labels of the actions for more information on what each action computes

distanceThe DISTANCE action with label distance calculates the following quantities:
 Quantity   
 Type   
 Description  
distance
scalar
the DISTANCE between this pair of atoms: DISTANCECalculate the distance/s between pairs of atoms. More details ATOMSthe pair of atom that we are calculating the distance between=1,2
distanceNThe DISTANCE action with label distanceN calculates the following quantities:
 Quantity   
 Type   
 Description  
distanceN
scalar
the DISTANCE between this pair of atoms: DISTANCECalculate the distance/s between pairs of atoms. More details ATOMSthe pair of atom that we are calculating the distance between=1,2 NUMERICAL_DERIVATIVES calculate the derivatives for these quantities numerically
DUMPDERIVATIVESDump the derivatives with respect to the input parameters for scalar values (generally CVs, functions or biases). More details ARGthe labels of the values whose derivatives should be output=distance,distanceN STRIDE the frequency with which the derivatives should be output=1 FILEthe name of the file on which to output the derivatives=deriv

This input outputs the derivative of the distance with respect to the atom positions and the cell vectors (virial-like form). It will thus output 15 deriatives for the two quantities output - the derivatives with respect to the x,y and z components of the input atoms and the 9 components of the virial.

By contast the following input will only output 1 derivative; namely, the derivative of the switching function, f, with respect to the input distance, d.

Click on the labels of the actions for more information on what each action computes

dThe DISTANCE action with label d calculates the following quantities:
 Quantity   
 Type   
 Description  
d
scalar
the DISTANCE between this pair of atoms: DISTANCECalculate the distance/s between pairs of atoms. More details ATOMSthe pair of atom that we are calculating the distance between=1,2
fThe LESS_THAN action with label f calculates the following quantities:
 Quantity   
 Type   
 Description  
f
scalar
a function that is one if the input is less than a threshold: LESS_THANUse a switching function to determine how many of the input variables are less than a certain cutoff. More details ARGthe values input to this function=d SWITCHThis keyword is used if you want to employ an alternative to the continuous swiching function defined above={RATIONAL R_0=0.2}
DUMPDERIVATIVESDump the derivatives with respect to the input parameters for scalar values (generally CVs, functions or biases). More details ARGthe labels of the values whose derivatives should be output=f STRIDE the frequency with which the derivatives should be output=1 FILEthe name of the file on which to output the derivatives=deriv

You can only use this command to output the derivatives of rank 0 (scalar) values. You cannot use it to output derivatives of vector, matrix of function values.

Syntax

The following table describes the keywords and options that can be used with this action