# ddeint

**Repository Path**: mirrors_Zulko/ddeint

## Basic Information

- **Project Name**: ddeint
- **Description**: Scipy-based Delay Differential Equation (DDE) solver
- **Primary Language**: Unknown
- **License**: CC0-1.0
- **Default Branch**: master
- **Homepage**: None
- **GVP Project**: No

## Statistics

- **Stars**: 0
- **Forks**: 0
- **Created**: 2020-09-26
- **Last Updated**: 2026-02-15

## Categories & Tags

**Categories**: Uncategorized

**Tags**: None

## README

# ddeint

[![PyPI](https://img.shields.io/pypi/v/ddeint.svg)](https://pypi.org/project/ddeint/)
[![Tests](https://github.com/zulko/ddeint/actions/workflows/test.yml/badge.svg)](https://github.com/zulko/ddeint/actions/workflows/test.yml)
[![Changelog](https://img.shields.io/github/v/release/zulko/ddeint?include_prereleases&label=changelog)](https://github.com/zulko/ddeint/releases)


Scipy-based delay differential equation (DDE) solver. See the docstrings and examples for more infos.

## Examples


```python
from pylab import cos, linspace, subplots
from ddeint import ddeint

# We solve the following system:
# Y(t) = 1 for t < 0
# dY/dt = -Y(t - 3cos(t)**2) for t > 0

def values_before_zero(t):
    return 1

def model(Y, t):
    return -Y(t - 3 * cos(Y(t)) ** 2)

tt = linspace(0, 30, 2000)
yy = ddeint(model, values_before_zero, tt)

fig, ax = subplots(1, figsize=(4, 4))
ax.plot(tt, yy)
ax.figure.savefig("variable_delay.jpeg")
```

![screenshot](https://github.com/Zulko/ddeint/raw/master/examples/variable_delay.jpeg)

```python
from pylab import array, linspace, subplots
from ddeint import ddeint

# We solve the following system:
# X(t) = 1 (t < 0)
# Y(t) = 2 (t < 0)
# dX/dt = X * (1 - Y(t-d)) / 2
# dY/dt = -Y * (1 - X(t-d)) / 2


def model(Y, t, d):
    x, y = Y(t)
    xd, yd = Y(t - d)
    return array([0.5 * x * (1 - yd), -0.5 * y * (1 - xd)])


g = lambda t: array([1, 2])
tt = linspace(2, 30, 20000)

fig, ax = subplots(1, figsize=(4, 4))

for d in [0, 0.2]:
    print("Computing for d=%.02f" % d)
    yy = ddeint(model, g, tt, fargs=(d,))
    # WE PLOT X AGAINST Y
    ax.plot(yy[:, 0], yy[:, 1], lw=2, label="delay = %.01f" % d)

ax.figure.savefig("lotka.jpeg")
```

![screenshot](https://github.com/Zulko/ddeint/raw/master/examples/lotka.jpeg)

## Licence


Public domain. Everyone is welcome to contribute !

## Installation

Install with pip:

```
pip install ddeint 
```

Or install locally in dev mode with:

```
pip install -e . 
```