#!/usr/bin/env python3
"""

Bickley jet iLE
===============

Compute the iLE field for the bickley jet.
"""

# Author: ajarvis

import numpy as np
import matplotlib.pyplot as plt
from numbacs.flows import get_predefined_callable
from numbacs.diagnostics import ile_2D_func
# %%
# Get flow
# --------------
# Set the initial time, retrieve a jit-callable for the flow, and set up domain.

# set time at which to compute iLE
t0 = 0.0

# retrieve function pointer, parameters, and domain for double gyre flow.
vel_func, domain = get_predefined_callable("bickley_jet")

# set up domain
# set up domain
dx = 0.05
dy = 0.05
x = np.arange(domain[0][0], domain[0][1] + dx, dx)
y = np.arange(domain[1][0], domain[1][1] + dy, dy)
dx = x[1] - x[0]
dy = y[1] - y[0]

# %%
# iLE
# ---------
# Compute iLE from velocity function at t = t0.
ile = ile_2D_func(vel_func, x, y, t0=t0)

# %%
# Plot
# ----
# Plot the results.
fig, ax = plt.subplots(dpi=200)
ax.contourf(x, y, ile.T, levels=80)
ax.set_aspect("equal")
plt.show()