netsse.model.envir_cond.wavespec1dto2d
======================================

.. py:function:: netsse.model.envir_cond.wavespec1dto2d(S1d, theta, theta0, s)

   Transforms a 1-D wave spectrum into a 2-D wave spectrum.

   A cosine-2s function is used for the directional spreading distribution.

   :param S1d: 1-D wave spectrum.
   :type S1d: array_like of shape (Nfreq,)
   :param theta: Vector of wave headings [deg] at which the 2-D spectrum must be computed.
   :type theta: array_like of shape (Ntheta,)
   :param theta0: Mean wave direction [deg].
   :type theta0: float
   :param s: Spreading parameter [-], related to the exponent of the cosine function.
   :type s: float

   :returns: * **S2d** (*array_like of shape (Nfreq,Ntheta)*) -- 2-D wave spectrum, as a function of both the frequency and the wave
               heading [deg].
             * **D_theta** (*array_like of shape (1,Ntheta)*) -- Directional spreading function, as a function of the wave heading [deg].

   .. rubric:: References

   Naess, Arvid, and Torgeir Moan. 2010. Stochastic Dynamics of
   Marine Structures. Stochastic Dynamics of Marine Structures. Vol.
   9780521881555. Cambridge University Press.
   https://doi.org/10.1017/CBO9781139021364.

   .. rubric:: Example

   >>> S2d = wavespec1dto2d(S1d,theta,theta0,s)