def singlediode(photocurrent, saturation_current, resistance_series,<EOL>resistance_shunt, nNsVth, ivcurve_pnts=None,<EOL>method='<STR_LIT>'):
<EOL>if method.lower() == '<STR_LIT>':<EOL><INDENT>out = _singlediode._lambertw(<EOL>photocurrent, saturation_current, resistance_series,<EOL>resistance_shunt, nNsVth, ivcurve_pnts<EOL>)<EOL>i_sc, v_oc, i_mp, v_mp, p_mp, i_x, i_xx = out[:<NUM_LIT:7>]<EOL>if ivcurve_pnts:<EOL><INDENT>ivcurve_i, ivcurve_v = out[<NUM_LIT:7>:]<EOL><DEDENT><DEDENT>else:<EOL><INDENT>args = (photocurrent, saturation_current, resistance_series,<EOL>resistance_shunt, nNsVth)  <EOL>v_oc = _singlediode.bishop88_v_from_i(<EOL><NUM_LIT:0.0>, *args, method=method.lower()<EOL>)<EOL>i_mp, v_mp, p_mp = _singlediode.bishop88_mpp(<EOL>*args, method=method.lower()<EOL>)<EOL>i_sc = _singlediode.bishop88_i_from_v(<EOL><NUM_LIT:0.0>, *args, method=method.lower()<EOL>)<EOL>i_x = _singlediode.bishop88_i_from_v(<EOL>v_oc / <NUM_LIT>, *args, method=method.lower()<EOL>)<EOL>i_xx = _singlediode.bishop88_i_from_v(<EOL>(v_oc + v_mp) / <NUM_LIT>, *args, method=method.lower()<EOL>)<EOL>if ivcurve_pnts:<EOL><INDENT>vd = v_oc * (<EOL>(<NUM_LIT> - np.logspace(np.log10(<NUM_LIT>), <NUM_LIT:0.0>,<EOL>ivcurve_pnts)) / <NUM_LIT><EOL>)<EOL>ivcurve_i, ivcurve_v, _ = _singlediode.bishop88(vd, *args)<EOL><DEDENT><DEDENT>out = OrderedDict()<EOL>out['<STR_LIT>'] = i_sc<EOL>out['<STR_LIT>'] = v_oc<EOL>out['<STR_LIT>'] = i_mp<EOL>out['<STR_LIT>'] = v_mp<EOL>out['<STR_LIT>'] = p_mp<EOL>out['<STR_LIT>'] = i_x<EOL>out['<STR_LIT>'] = i_xx<EOL>if ivcurve_pnts:<EOL><INDENT>out['<STR_LIT:v>'] = ivcurve_v<EOL>out['<STR_LIT:i>'] = ivcurve_i<EOL><DEDENT>if isinstance(photocurrent, pd.Series) and not ivcurve_pnts:<EOL><INDENT>out = pd.DataFrame(out, index=photocurrent.index)<EOL><DEDENT>return out<EOL>
Solve the single-diode model to obtain a photovoltaic IV curve.

Singlediode solves the single diode equation [1]

.. math::

    I = IL - I0*[exp((V+I*Rs)/(nNsVth))-1] - (V + I*Rs)/Rsh

for ``I`` and ``V`` when given ``IL, I0, Rs, Rsh,`` and ``nNsVth
(nNsVth = n*Ns*Vth)`` which are described later. Returns a DataFrame
which contains the 5 points on the I-V curve specified in
SAND2004-3535 [3]. If all IL, I0, Rs, Rsh, and nNsVth are scalar, a
single curve will be returned, if any are Series (of the same
length), multiple IV curves will be calculated.

The input parameters can be calculated using calcparams_desoto from
meteorological data.

Parameters
----------
photocurrent : numeric
    Light-generated current (photocurrent) in amperes under desired
    IV curve conditions. Often abbreviated ``I_L``.
    0 <= photocurrent

saturation_current : numeric
    Diode saturation current in amperes under desired IV curve
    conditions. Often abbreviated ``I_0``.
    0 < saturation_current

resistance_series : numeric
    Series resistance in ohms under desired IV curve conditions.
    Often abbreviated ``Rs``.
    0 <= resistance_series < numpy.inf

resistance_shunt : numeric
    Shunt resistance in ohms under desired IV curve conditions.
    Often abbreviated ``Rsh``.
    0 < resistance_shunt <= numpy.inf

nNsVth : numeric
    The product of three components. 1) The usual diode ideal factor
    (n), 2) the number of cells in series (Ns), and 3) the cell
    thermal voltage under the desired IV curve conditions (Vth). The
    thermal voltage of the cell (in volts) may be calculated as
    ``k*temp_cell/q``, where k is Boltzmann's constant (J/K),
    temp_cell is the temperature of the p-n junction in Kelvin, and
    q is the charge of an electron (coulombs).
    0 < nNsVth

ivcurve_pnts : None or int, default None
    Number of points in the desired IV curve. If None or 0, no
    IV curves will be produced.

method : str, default 'lambertw'
    Determines the method used to calculate points on the IV curve. The
    options are ``'lambertw'``, ``'newton'``, or ``'brentq'``.

Returns
-------
OrderedDict or DataFrame

The returned dict-like object always contains the keys/columns:

    * i_sc - short circuit current in amperes.
    * v_oc - open circuit voltage in volts.
    * i_mp - current at maximum power point in amperes.
    * v_mp - voltage at maximum power point in volts.
    * p_mp - power at maximum power point in watts.
    * i_x - current, in amperes, at ``v = 0.5*v_oc``.
    * i_xx - current, in amperes, at ``V = 0.5*(v_oc+v_mp)``.

If ivcurve_pnts is greater than 0, the output dictionary will also
include the keys:

    * i - IV curve current in amperes.
    * v - IV curve voltage in volts.

The output will be an OrderedDict if photocurrent is a scalar,
array, or ivcurve_pnts is not None.

The output will be a DataFrame if photocurrent is a Series and
ivcurve_pnts is None.

Notes
-----
If the method is ``'lambertw'`` then the solution employed to solve the
implicit diode equation utilizes the Lambert W function to obtain an
explicit function of :math:`V=f(I)` and :math:`I=f(V)` as shown in [2].

If the method is ``'newton'`` then the root-finding Newton-Raphson method
is used. It should be safe for well behaved IV-curves, but the ``'brentq'``
method is recommended for reliability.

If the method is ``'brentq'`` then Brent's bisection search method is used
that guarantees convergence by bounding the voltage between zero and
open-circuit.

If the method is either ``'newton'`` or ``'brentq'`` and ``ivcurve_pnts``
are indicated, then :func:`pvlib.singlediode.bishop88` [4] is used to
calculate the points on the IV curve points at diode voltages from zero to
open-circuit voltage with a log spacing that gets closer as voltage
increases. If the method is ``'lambertw'`` then the calculated points on
the IV curve are linearly spaced.

References
-----------
[1] S.R. Wenham, M.A. Green, M.E. Watt, "Applied Photovoltaics" ISBN
0 86758 909 4

[2] A. Jain, A. Kapoor, "Exact analytical solutions of the
parameters of real solar cells using Lambert W-function", Solar
Energy Materials and Solar Cells, 81 (2004) 269-277.

[3] D. King et al, "Sandia Photovoltaic Array Performance Model",
SAND2004-3535, Sandia National Laboratories, Albuquerque, NM

[4] "Computer simulation of the effects of electrical mismatches in
photovoltaic cell interconnection circuits" JW Bishop, Solar Cell (1988)
https://doi.org/10.1016/0379-6787(88)90059-2

See also
--------
sapm
calcparams_desoto
pvlib.singlediode.bishop88