1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
|
#################
ADIOS2 query API
#################
The query API in ADIOS2 allows a client to pass a query in XML or json format,
and get back a list of blocks or sub-blocks that contains hits.
Both BP4 and BP5 engines are supported.
The interface
=============
User is expected to pass a query file (configFile), and init a read engine (engine)
to construct a query and evaluate using the engine.
(note that the engine and query should be using the same ADIOS IO)
.. code-block:: c++
class QueryWorker
{
public:
// configFile has query, can be either xml or json
QueryWorker(const std::string &configFile, adios2::Engine &engine);
// touched_blocks is a list of regions specified by (start, count),
// that contains data that satisfies the query file
void GetResultCoverage(std::vector<adios2::Box<adios2::Dims>> &touched_blocks);
...
}
A Sample Compound Query
-----------------------
This query targets a 1D variable "doubleV", data of interest is (x > 6.6) or (x < -0.17) or (2.8 < x < 2.9)
In addition, this query also specied an output region [start=5,count=80].
.. code-block:: xml
<adios-query>
<io name="query">
<var name="doubleV">
<boundingbox start="5" count="80"/>
<op value="OR">
<range compare="GT" value="6.6"/>
<range compare="LT" value="-0.17"/>
<op value="AND">
<range compare="LT" value="2.9"/>
<range compare="GT" value="2.8"/>
</op>
</op>
</var>
</io>
</adios-query>
Code EXAMPLES:
==============
C++:
----
.. code-block:: c++
while (reader.BeginStep() == adios2::StepStatus::OK)
{
adios2::QueryWorker w = adios2::QueryWorker(queryFile, reader);
w.GetResultCoverage(touched_blocks);
std::cout << " ... now can read out touched blocks ... size=" << touched_blocks.size()
<< std::endl;
}
The Full C++ example is here:
https://github.com/ornladios/ADIOS2/blob/master/examples/query/test.cpp
Python:
-------
.. code-block:: python
while (reader.BeginStep() == adios2.StepStatus.OK):
# say only rank 0 wants to process result
var = [queryIO.InquireVariable("T")]
if (rank == 0):
touched_blocks = w.GetResult()
doAnalysis(reader, touched_blocks, var)
Full python example is here:
https://github.com/ornladios/ADIOS2/blob/master/testing/adios2/bindings/python/TestQuery.py
This example generates data, the query file (in xml) and runs the query, all in python.
|
