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DESolve

Getting started

Requirements

Section titled “Requirements”
  • Python 3.8 or newer
  • pip
  • numpy
  • scipy

Install the package

Section titled “Install the package”

Create a virtual environment and install the project in editable mode:

Terminal window
python -m venv .venv
source .venv/bin/activate
python -m pip install --upgrade pip
python -m pip install -e ".[dev]"

If you also want the notebook tooling:

Terminal window
python -m pip install -e ".[dev,notebooks]"

Smoke test

Section titled “Smoke test”

Confirm the solver imports cleanly:

Terminal window
python -c "from desolve.DESolver import DESolver; DESolver(); print('ok')"

First solve

Section titled “First solve”

The example below advances the scalar ODE u' = -u using RK4.

import numpy as np
from desolve.DESolver import DESolver


def rhs(t, u, ctx):
    f = -u
    jac = -np.eye(u.size, dtype=ctx["data-type"])
    return f, jac


solver = DESolver()
solver.set_function_context({"data-type": np.float64})
solver.setup(keep_history=True)


solver.set_rhs(rhs)
solver.set_initial_solution(np.array([1.0], dtype=np.float64))
solver.set_duration(t_start=0.0, t_end=1.0, dt=1e-2)
solver.set_method("RK4")


solver.solve()
t, u = solver.get_trajectory()
print(t[-1], u[:, -1])

Next step

Section titled “Next step”

Once the basic example works, move to the solver workflow page to understand the typical call sequence and where method selection and problem setup fit together.