How to read data from XML¶
For paminco, we chose XML as our standard data format for networks. An XML file specifies edges (obligatory), nodes (optional), edge cost (optional) and commodities (optional).
1. Read edges and Nodes¶
1.1 From -> to¶
We start by specyfying and reading in only the egde data.
import paminco
xml1 = \
"""
<network>
<edges>
<edge from="A" to="B"></edge>
<edge from="A" to="C"></edge>
<edge from="B" to="C"></edge>
<edge from="B" to="D"></edge>
<edge from="C" to="D"></edge>
</edges>
</network>
"""
edges = paminco.net.Edges.from_xml(xml1)
edges.to_df()
| source_lbl | target_lbl | s | t | lb | ub | |
|---|---|---|---|---|---|---|
| 0 | A | B | 0 | 1 | 0.0 | inf |
| 1 | A | C | 0 | 2 | 0.0 | inf |
| 2 | B | C | 1 | 2 | 0.0 | inf |
| 3 | B | D | 1 | 3 | 0.0 | inf |
| 4 | C | D | 2 | 3 | 0.0 | inf |
1.2 Edge bounds¶
By default, paminco constructs directed edges with bounds (0, infinity).
However, we can specify them in the XML file:
xml2 = \
"""
<network>
<edges>
<edge from="A" to="B" lb="0" ub="200"></edge>
<edge from="A" to="C" lb="-200" ub="200"></edge>
<edge from="B" to="C" lb="10" ub="11"></edge>
<edge from="B" to="D" lb="1" ub="1.1"></edge>
<edge from="C" to="D" lb="-5" ub="3"></edge>
</edges>
</network>
"""
edges = paminco.net.Edges.from_xml(xml2)
edges.to_df()
| source_lbl | target_lbl | s | t | lb | ub | |
|---|---|---|---|---|---|---|
| 0 | A | B | 0 | 1 | 0.0 | 200.0 |
| 1 | A | C | 0 | 2 | -200.0 | 200.0 |
| 2 | B | C | 1 | 2 | 10.0 | 11.0 |
| 3 | B | D | 1 | 3 | 1.0 | 1.1 |
| 4 | C | D | 2 | 3 | -5.0 | 3.0 |
1.3 Node attributes¶
We can add a <nodes> tag to the XML and define node locations:
xml3 = \
"""
<network>
<nodes>
<node node="A" x="0" y="0"/>
<node node="B" x="0" y="3"/>
<node node="C" x="3" y="0"/>
<node node="D" x="3" y="3"/>
</nodes>
<edges>
<edge from="A" to="B"></edge>
<edge from="A" to="C"></edge>
<edge from="B" to="C"></edge>
<edge from="B" to="D"></edge>
<edge from="C" to="D"></edge>
</edges>
</network>
"""
nodes = paminco.net.Nodes.from_xml(xml3)
nodes.to_df()
| label | zone | x | y | |
|---|---|---|---|---|
| 0 | A | False | 0.0 | 0.0 |
| 1 | B | False | 0.0 | 3.0 |
| 2 | C | False | 3.0 | 0.0 |
| 3 | D | False | 3.0 | 3.0 |
2. Read commodities¶
xml4 = \
"""
<network>
<commodities>
<commodity>
<b node="1" value="-160.0"/>
<b node="2" value="-60.0"/>
<b node="7" value="100.0"/>
<b node="14" value="120.0"/>
</commodity>
</commodities>
<edges>
<edge from="A" to="B"></edge>
<edge from="A" to="C"></edge>
<edge from="B" to="C"></edge>
<edge from="B" to="D"></edge>
<edge from="C" to="D"></edge>
</edges>
</network>
"""
dv = paminco.net.demand_vector(xml4, is_label=False)
dv.commodities[0]
CommodityMultiSourceSink @ 0x7f41cba087c0
1 : -160.0
2 : -60.0
7 : 100.0
14 : 120.0