<｜begin▁of▁sentence｜>### Instruction:
As a greenhouse grower, you're tasked with optimizing the layout of your greenhouse to ensure efficient growth and utilization of space. Imagine you have a blueprint of your greenhouse represented as a graph, stored in a file named 'greenhouse_layout.gml'. Your goal is to use a specialized tool called 'layout_graphopt' from the greenhouse management software to arrange the plants in the greenhouse effectively. This tool employs attractive and repelling forces to simulate the natural growth patterns of plants until they reach equilibrium or a maximum number of iterations is completed.
### Response:
import igraph as ig
import json

# Load a graph from a file
file_path = 'network_file.gml'
g = ig.Graph.Read_GML(file_path)

# Use the graphopt layout algorithm with custom parameters
g_layout = g.layout_graphopt(niter=200, node_charge=-30, node_mass=5, spring_length=50, spring_constant=0.01, max_sa_movement=5)

# After the layout is computed, you can use it to plot the graph
ig.plot(g, layout=g_layout, vertex_label=g.vs['name'])
<|EOT|>
