Quickstart

This simple example demonstrates the basics of PathSim by integrating a cosine function to produce a sine wave.

Setup

First, import the necessary modules:

import numpy as np
import matplotlib.pyplot as plt

from pathsim import Simulation, Connection
from pathsim.blocks import Source, Integrator, Scope

# Apply custom plotting style
plt.style.use('pathsim_docs.mplstyle')

Build the System

Define the blocks that make up our system:

# Define the blocks of our system
Sr = Source(np.cos)                    # Source block that outputs cos(t)
In = Integrator()                       # Integrator block
Sc = Scope(labels=["cos", "sin"])      # Scope to record signals

Create the Simulation

Connect the blocks and create a simulation instance:

# Create simulation with blocks and connections
Sim = Simulation(
    blocks=[Sr, In, Sc],
    connections=[
        Connection(Sr, In),      # cosine → integrator
        Connection(Sr, Sc[0]),   # cosine → scope channel 0
        Connection(In, Sc[1]),   # sine → scope channel 1
    ],
    dt=0.01
)

2025-10-23 15:26:26,728 - INFO - LOGGING (log: True)
2025-10-23 15:26:26,729 - INFO - BLOCK (type: Source, dynamic: False, events: 0)
2025-10-23 15:26:26,730 - INFO - BLOCK (type: Integrator, dynamic: True, events: 0)
2025-10-23 15:26:26,730 - INFO - BLOCK (type: Scope, dynamic: False, events: 0)
2025-10-23 15:26:26,731 - INFO - GRAPH (nodes: 3, edges: 3, alg. depth: 1, loop depth: 0, runtime: 0.030ms)

Run and Visualize

Execute the simulation for 10 time units and plot the results:

# Run for 10 time units
Sim.run(10)

# Plot the scope
Sc.plot(lw=2)
plt.show()

2025-10-23 15:26:26,736 - INFO - STARTING -> TRANSIENT (Duration: 10.00s)
2025-10-23 15:26:26,737 - INFO - TRANSIENT:   0% | elapsed: 00:00:00 (eta: --:--:--) | 0 steps (N/A steps/s)
2025-10-23 15:26:26,745 - INFO - TRANSIENT:  20% | elapsed: 00:00:00 (eta: --:--:--) | 200 steps (24514.4 steps/s)
2025-10-23 15:26:26,753 - INFO - TRANSIENT:  40% | elapsed: 00:00:00 (eta: --:--:--) | 401 steps (24752.9 steps/s)
2025-10-23 15:26:26,761 - INFO - TRANSIENT:  60% | elapsed: 00:00:00 (eta: --:--:--) | 601 steps (23487.4 steps/s)
2025-10-23 15:26:26,770 - INFO - TRANSIENT:  80% | elapsed: 00:00:00 (eta: --:--:--) | 801 steps (24384.3 steps/s)
2025-10-23 15:26:26,778 - INFO - TRANSIENT: 100% | elapsed: 00:00:00 (eta: --:--:--) | 1001 steps (24770.8 steps/s)
2025-10-23 15:26:26,778 - INFO - TRANSIENT: 100% | elapsed: 00:00:00 (eta: --:--:--) | 1001 steps (23542.1 avg steps/s)
2025-10-23 15:26:26,778 - INFO - FINISHED -> TRANSIENT (total steps: 1001, successful: 1001, runtime: 42.52 ms)

The plot shows both the original cosine wave and the integrated sine wave, demonstrating how PathSim can simulate continuous-time systems through block-based modeling.