CHFL_SELECTION
¶
-
typedef struct CHFL_SELECTION CHFL_SELECTION¶
An opaque type handling a selection.
CHFL_SELECTION
allow to select atoms in aCHFL_FRAME
, from a selection language. The selection language is built by combining basic operations. Each basic operation follows the<selector>[(<variable>)] <operator> <value>
structure, where<operator>
is a comparison operator in== != < <= > >=
.
Here is the full list of functions acting on CHFL_SELECTION
:
-
CHFL_SELECTION *chfl_selection(const char *selection)¶
Create a new selection from the given
selection
string.The caller of this function should free the associated memory using
chfl_free
.- Returns:
A pointer to the selection, or NULL in case of error. You can use
chfl_last_error
to learn about the error.
-
CHFL_SELECTION *chfl_selection_copy(const CHFL_SELECTION *selection)¶
Get a copy of a
selection
.The copy does not contains any state, and
chfl_selection_evaluate
must be called again before usingchfl_selection_matches
.The caller of this function should free the associated memory using
chfl_free
.- Returns:
A pointer to the new selection, or NULL in case of error. You can use
chfl_last_error
to learn about the error.
-
chfl_status chfl_selection_size(const CHFL_SELECTION *selection, uint64_t *size)¶
Get the size of a
selection
insize
.The size of a selection is the number of atoms we are selecting together. This value is 1 for the ‘atom’ context, 2 for the ‘pair’ and ‘bond’ context, 3 for the ‘three’ and ‘angles’ contexts and 4 for the ‘four’ and ‘dihedral’ contexts.
- Returns:
The operation status code. You can use
chfl_last_error
to learn about the error if the status code is notCHFL_SUCCESS
.
-
chfl_status chfl_selection_string(const CHFL_SELECTION *selection, char *string, uint64_t buffsize)¶
Get the selection string used to create a given
selection
in thestring
buffer.The buffer size must be passed in
buffsize
. This function will truncate the selection string to fit in the buffer.- Returns:
The operation status code. You can use
chfl_last_error
to learn about the error if the status code is notCHFL_SUCCESS
.
-
chfl_status chfl_selection_evaluate(CHFL_SELECTION *selection, const CHFL_FRAME *frame, uint64_t *n_matches)¶
Evaluate a
selection
for a givenframe
, and store the number of matches inn_matches
.Use the
chfl_selection_matches
function to get the matches for this selection.- Returns:
The operation status code. You can use
chfl_last_error
to learn about the error if the status code is notCHFL_SUCCESS
.
-
chfl_status chfl_selection_matches(const CHFL_SELECTION *selection, chfl_match matches[], uint64_t n_matches)¶
Get the matches for a
selection
after a call tochfl_selection_evaluate
, inmatches
.The size of the
matches
array must be passed inn_matches
.- Returns:
The operation status code. You can use
chfl_last_error
to learn about the error if the status code is notCHFL_SUCCESS
.
-
struct chfl_match¶
A
chfl_match
is a set of atomic indexes matching a given selection. The size of a match depends on the associated selection, and can vary from 1 toCHFL_MAX_SELECTION_SIZE
.
-
CHFL_MAX_SELECTION_SIZE¶
Maximal size for a selection match.