Source code for wavespectra.construct.jonswap

import numpy as np
from typing_extensions import deprecated
from wavespectra.construct.helpers import (
    spread,
    check_coordinates,
    arrange_inputs,
    make_dataset,
)




@deprecated(
    "All functions and classes in `wavespectra.construct` will be replaced in "
    "**4.0.0** by a new spectral reconstruction api.",
)
def jonswap(
    tp,
    dp,
    alpha,
    gamma=3.3,
    dspr=20,
    freqs=np.arange(0.04, 1.0, 0.02),
    dirs=np.arange(0, 360, 10),
    coordinates=[],
    sumpart=True,
):
    """Constructs JONSWAP spectra."""
    check_coordinates(tp, coordinates)

    # Arrange inputs
    tp_m, dp_m, alpha_m, gamma_m, dspr_m = arrange_inputs(tp, dp, alpha, gamma, dspr)
    f = freqs.reshape((-1, 1))

    # Calculate JONSWAP
    fp = 1.0 / np.array(tp_m)
    sig = np.where(f <= fp, 0.07, 0.09)
    r = np.exp(-(f - fp) ** 2.0 / (2 * sig ** 2 * fp ** 2))
    S = 0.0617 * alpha_m * f ** (-5) * np.exp(-1.25 * (f / fp) ** (-4)) * gamma_m ** r

    # Apply spreading
    G1 = spread(dp_m, dspr_m, dirs)
    spec = S * G1

    # sum partitions
    if sumpart:
        idimpart = [i for i, t in enumerate(coordinates) if t[0] == "part"]
        if idimpart:
            spec = np.sum(spec, axis=idimpart[0])
            coordinates.pop(idimpart[0])

    return make_dataset(spec, freqs, dirs, coordinates)