qubed/docs/quickstart.md
2025-02-19 14:17:47 +00:00

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# Quickstart
## Installation
```bash
pip install qubed
```
## Usage
Make an uncompressed qube:
```{code-cell} python3
from qubed import Qube
q = Qube.from_dict({
"class=od" : {
"expver=0001": {"param=1":{}, "param=2":{}},
"expver=0002": {"param=1":{}, "param=2":{}},
},
"class=rd" : {
"expver=0001": {"param=1":{}, "param=2":{}, "param=3":{}},
"expver=0002": {"param=1":{}, "param=2":{}},
},
})
print(f"{q.n_leaves = }, {q.n_nodes = }")
q
```
Compress it:
```{code-cell} python3
cq = q.compress()
assert cq.n_leaves == q.n_leaves
print(f"{cq.n_leaves = }, {cq.n_nodes = }")
cq
```
### Quick Tree Construction
One of the quickest ways to construct non-trivial trees is to use the `Qube.from_datacube` method to construct dense trees and then use the set operations to combine or intersect them:
```{code-cell} python3
q = Qube.from_datacube({
"class": "d1",
"dataset": ["climate-dt", "another-value"],
'generation': ['1', "2", "3"],
})
r = Qube.from_datacube({
"class": "d1",
"dataset": ["weather-dt", "climate-dt"],
'generation': ['1', "2", "3", "4"],
})
q | r
```
### Iteration / Flattening
Iterate over the leaves:
```{code-cell} python3
for i, identifier in enumerate(cq.leaves()):
print(identifier)
if i > 10:
print("...")
break
```
Iterate over the datacubes:
```{code-cell} python3
cq.datacubes()
```
### A Real World Example
Load a larger example qube:
```{code-cell} python3
import requests
qube_json = requests.get("https://github.com/ecmwf/qubed/raw/refs/heads/main/tests/example_qubes/climate_dt.json").json()
climate_dt = Qube.from_json(qube_json)
# Using the html or print methods is optional but lets you specify things like the depth of the tree to display.
print(f"{climate_dt.n_leaves = }, {climate_dt.n_nodes = }")
climate_dt.html(depth=1) # Limit how much is open initially, click leave to see more.
```
Select a subset of the tree:
```{code-cell} python3
climate_dt.select({
"activity": "scenariomip"
}).html(depth=1)
```
Use `.span("key")` to get the set of possibles values for a key, note this includes anywhere this key appears in the tree.
```{code-cell} python3
climate_dt.span("activity")
```
Use `.axes()` to get the span of every key in one go.
```{code-cell} python3
axes = climate_dt.axes()
for key, values in axes.items():
print(f"{key} : {list(values)[:10]}")
```
### Set Operations
The union/intersection/difference of two dense datacubes is not itself dense.
```{code-cell} python3
A = Qube.from_dict({"a=1/2/3" : {"b=i/j/k" : {}},})
B = Qube.from_dict({"a=2/3/4" : {"b=j/k/l" : {}},})
A.print(), B.print();
```
Union:
```{code-cell} python3
(A | B).print();
```
Intersection:
```{code-cell} python3
(A & B).print();
```
Difference:
```{code-cell} python3
(A - B).print();
```
Symmetric Difference:
```{code-cell} python3
(A ^ B).print();
```