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ATLAS Offline Software
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a struct that contains meta-information about each column that's needed to interface the column with the columnar data store More...
#include <ColumnInfo.h>
Public Attributes | |
| std::string | name {} |
| the name of the column More... | |
| unsigned | index = 0u |
| the index of the column in the data array More... | |
| const std::type_info * | type = nullptr |
| the type of the individual entries in the column More... | |
| ColumnAccessMode | accessMode = ColumnAccessMode::input |
| the access mode for the column More... | |
| std::string | offsetName {} |
| the name of the offset column used for this column (or empty string for none) More... | |
| std::vector< unsigned > | fixedDimensions {} |
| the fixed dimensions this column has (if any) More... | |
| bool | isOffset = false |
| whether this is an offset column More... | |
| std::string | replacesColumn {} |
| whether this replaces another column More... | |
| bool | isOptional = false |
| whether this column is optional More... | |
| std::string | linkToName {} |
| the name of the column we link to (or empty string if we don't link to a column) More... | |
a struct that contains meta-information about each column that's needed to interface the column with the columnar data store
Definition at line 34 of file ColumnInfo.h.
| ColumnAccessMode columnar::ColumnInfo::accessMode = ColumnAccessMode::input |
the access mode for the column
Definition at line 58 of file ColumnInfo.h.
| std::vector<unsigned> columnar::ColumnInfo::fixedDimensions {} |
the fixed dimensions this column has (if any)
For the most part we use dynamic dimensions via offset maps, but sometimes the dimensions are hard-coded, which then uses these dimensions.
Definition at line 82 of file ColumnInfo.h.
| unsigned columnar::ColumnInfo::index = 0u |
the index of the column in the data array
Definition at line 46 of file ColumnInfo.h.
| bool columnar::ColumnInfo::isOffset = false |
whether this is an offset column
In part this is for consistency checks, i.e. other columns can only refer to this as an offset column if this is set. It also means that there needs to be an extra element in the column past the last "regular" one to hold the total number of entries in columns using this.
Definition at line 92 of file ColumnInfo.h.
| bool columnar::ColumnInfo::isOptional = false |
whether this column is optional
Essentially this indicates that the column can be skipped, and the tool will check whether the column is present before trying to use it. This allows to adapt the tool somewhat to different environments.
The downside here is that overall this is still a bit ambiguous, i.e. whoever links up the columns needs to decide whether it is needed. For columns that are not in the input file that's easy, there is no choice but omitting them. However, some columns only exist as a backup option for other columns, and ideally we don't want to load the backup columns when the main columns are missing. So either that needs to be set during configuration, or we need to add more meta-information for that case, or the user needs to do something smart (i.e. manual) in their code.
Definition at line 121 of file ColumnInfo.h.
| std::string columnar::ColumnInfo::linkToName {} |
the name of the column we link to (or empty string if we don't link to a column)
Some of our columns contain an index of an object in another column. This is the name of that other column. This can then be used for consistency checks, and could potentially also be used to aid in thinning operations to keep the link indices consistent.
So far we only have links that link to one specific column. If we need columns that link to multiple columns I will need to revisit how I do this. I'd probably turn this into a vector, and then have a separate column that contains the index in that vector for each index.
Definition at line 138 of file ColumnInfo.h.
| std::string columnar::ColumnInfo::name {} |
the name of the column
This is the primary way by which columns should be identified when interacting with the user, but it should only be used during the configuration. During the actual processing this should rely on the index for identification instead.
Definition at line 42 of file ColumnInfo.h.
| std::string columnar::ColumnInfo::offsetName {} |
the name of the offset column used for this column (or empty string for none)
Most of our columns do not represent a regular-shaped tensor, but has a different number of entries in each row, e.g. the column holding the muon-pt will have a different number of muons per event. To handle this, there needs to be a column that contains the offsets for each row.
There can be multiple irregularly shaped dimensions for a column, in which case this is just the name of the inner-most one. The outer-ones can be found by following the offset name in a chain.
Definition at line 74 of file ColumnInfo.h.
| std::string columnar::ColumnInfo::replacesColumn {} |
whether this replaces another column
For corrections it is quite typical that a column is meant to replace another column. In columnar land we will create genuinely new columns, in xAOD land we will usually overwrite the content of those columns. This member is used to indicate which column gets replaced.
Definition at line 102 of file ColumnInfo.h.
| const std::type_info* columnar::ColumnInfo::type = nullptr |
the type of the individual entries in the column
This should generally be something like float or int, neither be const-qualified nor in a container like std::vector<float>.
Definition at line 54 of file ColumnInfo.h.
1.8.18