# E_DENSITY_BQB

References: Brehm2018

Controls the output of the electron density to the losslessly compressed BQB file format, see [Brehm2018] (via LibBQB see https://brehm-research.de/bqb). Currently does not work with changing cell vector (NpT ensemble). [Edit on GitHub]

Subsections

- EACH

## Keywords

- SECTION_PARAMETERS

- ADD_LAST

- CHECK

- COMMON_ITERATION_LEVELS

- FILENAME

- HISTORY

- LOG_PRINT_KEY

- OPTIMIZE

- OVERWRITE

- PARAMETER_KEY

- SKIP_FIRST

- STORE_STEP_NUMBER

- __CONTROL_VAL

## Keyword descriptions

SECTION_PARAMETERS: enum = OFF

  Lone keyword: `SILENT`

  Usage: silent

  Valid values:

  - `ON`

  - `OFF`

  - `SILENT`

  - `LOW`

  - `MEDIUM`

  - `HIGH`

  - `DEBUG`

  Level starting at which this property is printed [Edit on GitHub]

ADD_LAST: enum = NO

  Usage: ADD_LAST (NO|NUMERIC|SYMBOLIC)

  Valid values:

  - `NO` Do not mark last iteration specifically

  - `NUMERIC` Mark last iteration with its iteration number

  - `SYMBOLIC` Mark last iteration with lowercase letter l

  If the last iteration should be added, and if it should be marked symbolically (with lowercase letter l) or with the iteration number. Not every iteration level is able to identify the last iteration early enough to be able to output. When this keyword is activated all iteration levels are checked for the last iteration step. [Edit on GitHub]

CHECK: logical = F

  Lone keyword: `T`

  Usage: CHECK T

  Performs an on-the-fly decompression of each compressed BQB frame to check whether the volumetric data exactly matches, and aborts the run if not so. [Edit on GitHub]

COMMON_ITERATION_LEVELS: integer = 0

  Usage: COMMON_ITERATION_LEVELS <INTEGER>

  How many iterations levels should be written in the same file (no extra information about the actual iteration level is written to the file) [Edit on GitHub]

FILENAME: string

  Usage: FILENAME ./filename

  controls part of the filename for output. use __STD_OUT__ (exactly as written here) for the screen or standard logger. use filename to obtain projectname-filename. use ./filename to get filename. A middle name (if present), iteration numbers and extension are always added to the filename. if you want to avoid it use =filename, in this case the filename is always exactly as typed. Please note that this can lead to clashes of filenames. [Edit on GitHub]

HISTORY: integer = 10

  Usage: HISTORY 10

  Controls how many previous steps are taken into account for extrapolation in compression. Use a value of 1 to compress the frames independently. [Edit on GitHub]

LOG_PRINT_KEY: logical = F

  Lone keyword: `T`

  Usage: LOG_PRINT_KEY <LOGICAL>

  This keywords enables the logger for the print_key (a message is printed on screen everytime data, controlled by this print_key, are written) [Edit on GitHub]

OPTIMIZE: enum = QUICK

  Usage: OPTIMIZE {OFF,QUICK,NORMAL,PATIENT,EXHAUSTIVE}

  Valid values:

  - `OFF` No optimization (use defaults)

  - `QUICK` Quick optimization

  - `NORMAL` Standard optimization

  - `PATIENT` Precise optimization

  - `EXHAUSTIVE` Exhaustive optimization

  Controls the time spent to optimize the parameters for compression efficiency. [Edit on GitHub]

OVERWRITE: logical = F

  Lone keyword: `T`

  Usage: OVERWRITE T

  Specify this keyword to overwrite the output BQB file if it already exists. By default, the data is appended to an existing file. [Edit on GitHub]

PARAMETER_KEY: string

  Usage: PARAMETER_KEY <KEY>

  Allows to supply previously optimized compression parameters via a parameter key (alphanumeric character sequence starting with ‘at’). Just leave away the ‘at’ sign here, because CP2k will otherwise assume it is a variable name in the input [Edit on GitHub]

SKIP_FIRST: logical = F

  Lone keyword: `T`

  Usage: SKIP_FIRST T

  Skips the first step of a MD run (avoids duplicate step if restarted). [Edit on GitHub]

STORE_STEP_NUMBER: logical = T

  Lone keyword: `T`

  Usage: STORE_STEP_NUMBER F

  Stores the step number and simulation time in the comment line of each BQB frame. Switch it off for binary compatibility with original CP2k CUBE files. [Edit on GitHub]

__CONTROL_VAL: integer = 8

  hidden parameter that controls storage, printing,… of the print_key [Edit on GitHub]