# Source code for openmc.deplete.integrators

import copy
from itertools import repeat

from .abc import Integrator, SIIntegrator, OperatorResult
from .cram import timed_deplete
from ._matrix_funcs import (
cf4_f1, cf4_f2, cf4_f3, cf4_f4, celi_f1, celi_f2,
leqi_f1, leqi_f2, leqi_f3, leqi_f4, rk4_f1, rk4_f4
)

__all__ = [
"PredictorIntegrator", "CECMIntegrator", "CF4Integrator",
"CELIIntegrator", "EPCRK4Integrator", "LEQIIntegrator",
"SICELIIntegrator", "SILEQIIntegrator"]

[docs]class PredictorIntegrator(Integrator):
r"""Deplete using a first-order predictor algorithm.

Implements the first-order predictor algorithm. This algorithm is
mathematically defined as:

.. math::
\begin{aligned}
y' &= A(y, t) y(t) \\
A_p &= A(y_n, t_n) \\
y_{n+1} &= \text{expm}(A_p h) y_n
\end{aligned}

Parameters
----------
operator : openmc.deplete.TransportOperator
Operator to perform transport simulations
timesteps : iterable of float
Array of timesteps in units of [s]. Note that values are not
cumulative.
power : float or iterable of float, optional
Power of the reactor in [W]. A single value indicates that
the power is constant over all timesteps. An iterable
indicates potentially different power levels for each timestep.
For a 2D problem, the power can be given in [W/cm] as long
as the "volume" assigned to a depletion material is actually
an area in [cm^2]. Either power or power_density must be
specified.
power_density : float or iterable of float, optional
Power density of the reactor in [W/gHM]. It is multiplied by
initial heavy metal inventory to get total power if power
is not speficied.

Attributes
----------
operator : openmc.deplete.TransportOperator
Operator to perform transport simulations
chain : openmc.deplete.Chain
Depletion chain
timesteps : iterable of float
Size of each depletion interval in [s]
power : iterable of float
Power of the reactor in [W] for each interval in :attr:timesteps
"""
_num_stages = 1

[docs]    def __call__(self, conc, rates, dt, power, _i=None):
"""Perform the integration across one time step

Parameters
----------
conc : numpy.ndarray
Initial concentrations for all nuclides in [atom]
rates : openmc.deplete.ReactionRates
Reaction rates from operator
dt : float
Time in [s] for the entire depletion interval
power : float
Power of the system in [W]
_i : int or None
Iteration index. Not used

Returns
-------
proc_time : float
Time spent in CRAM routines for all materials in [s]
conc_list : list of numpy.ndarray
Concentrations at end of interval
op_results : empty list
Kept for consistency with API. No intermediate calls to
operator with predictor

"""
proc_time, conc_end = timed_deplete(self.chain, conc, rates, dt)
return proc_time, [conc_end], []

[docs]class CECMIntegrator(Integrator):
r"""Deplete using the CE/CM algorithm.

Implements the second order CE/CM predictor-corrector algorithm
<https://doi.org/10.13182/NSE14-92>_.

"CE/CM" stands for constant extrapolation on predictor and constant
midpoint on corrector. This algorithm is mathematically defined as:

.. math::
\begin{aligned}
y' &= A(y, t) y(t) \\
A_p &= A(y_n, t_n) \\
y_m &= \text{expm}(A_p h/2) y_n \\
A_c &= A(y_m, t_n + h/2) \\
y_{n+1} &= \text{expm}(A_c h) y_n
\end{aligned}

Parameters
----------
operator : openmc.deplete.TransportOperator
Operator to perform transport simulations
timesteps : iterable of float
Array of timesteps in units of [s]. Note that values are not
cumulative.
power : float or iterable of float, optional
Power of the reactor in [W]. A single value indicates that
the power is constant over all timesteps. An iterable
indicates potentially different power levels for each timestep.
For a 2D problem, the power can be given in [W/cm] as long
as the "volume" assigned to a depletion material is actually
an area in [cm^2]. Either power or power_density must be
specified.
power_density : float or iterable of float, optional
Power density of the reactor in [W/gHM]. It is multiplied by
initial heavy metal inventory to get total power if power
is not speficied.

Attributes
----------
operator : openmc.deplete.TransportOperator
Operator to perform transport simulations
chain : openmc.deplete.Chain
Depletion chain
timesteps : iterable of float
Size of each depletion interval in [s]
power : iterable of float
Power of the reactor in [W] for each interval in :attr:timesteps
"""
_num_stages = 2

[docs]    def __call__(self, conc, rates, dt, power, _i=None):
"""Integrate using CE/CM

Parameters
----------
conc : numpy.ndarray
Initial concentrations for all nuclides in [atom]
rates : openmc.deplete.ReactionRates
Reaction rates from operator
dt : float
Time in [s] for the entire depletion interval
power : float
Power of the system [W]
_i : int, optional
Current iteration count. Not used

Returns
-------
proc_time : float
Time spent in CRAM routines for all materials in [s]
conc_list : list of numpy.ndarray
Concentrations at each of the intermediate points with
the final concentration as the last element
op_results : list of openmc.deplete.OperatorResult
Eigenvalue and reaction rates from transport simulations
"""
# deplete across first half of inteval
time0, x_middle = timed_deplete(self.chain, conc, rates, dt / 2)
res_middle = self.operator(x_middle, power)

# deplete across entire interval with BOS concentrations,
# MOS reaction rates
time1, x_end = timed_deplete(self.chain, conc, res_middle.rates, dt)

return time0 + time1, [x_middle, x_end], [res_middle]

[docs]class CF4Integrator(Integrator):
r"""Deplete using the CF4 algorithm.

Implements the fourth order commutator-free Lie algorithm
<https://doi.org/10.1016/S0167-739X(02)00161-9>_.
This algorithm is mathematically defined as:

.. math::
\begin{aligned}
F_1 &= h A(y_0) \\
y_1 &= \text{expm}(1/2 F_1) y_0 \\
F_2 &= h A(y_1) \\
y_2 &= \text{expm}(1/2 F_2) y_0 \\
F_3 &= h A(y_2) \\
y_3 &= \text{expm}(-1/2 F_1 + F_3) y_1 \\
F_4 &= h A(y_3) \\
y_4 &= \text{expm}( 1/4  F_1 + 1/6 F_2 + 1/6 F_3 - 1/12 F_4)
\text{expm}(-1/12 F_1 + 1/6 F_2 + 1/6 F_3 + 1/4  F_4) y_0
\end{aligned}

Parameters
----------
operator : openmc.deplete.TransportOperator
Operator to perform transport simulations
timesteps : iterable of float
Array of timesteps in units of [s]. Note that values are not
cumulative.
power : float or iterable of float, optional
Power of the reactor in [W]. A single value indicates that
the power is constant over all timesteps. An iterable
indicates potentially different power levels for each timestep.
For a 2D problem, the power can be given in [W/cm] as long
as the "volume" assigned to a depletion material is actually
an area in [cm^2]. Either power or power_density must be
specified.
power_density : float or iterable of float, optional
Power density of the reactor in [W/gHM]. It is multiplied by
initial heavy metal inventory to get total power if power
is not speficied.

Attributes
----------
operator : openmc.deplete.TransportOperator
Operator to perform transport simulations
chain : openmc.deplete.Chain
Depletion chain
timesteps : iterable of float
Size of each depletion interval in [s]
power : iterable of float
Power of the reactor in [W] for each interval in :attr:timesteps
"""
_num_stages = 4

[docs]    def __call__(self, bos_conc, bos_rates, dt, power, _i=None):
"""Perform the integration across one time step

Parameters
----------
bos_conc : numpy.ndarray
Initial concentrations for all nuclides in [atom]
bos_rates : openmc.deplete.ReactionRates
Reaction rates from operator
dt : float
Time in [s] for the entire depletion interval
power : float
Power of the system in [W]
_i : int, optional
Current depletion step index. Not used

Returns
-------
proc_time : float
Time spent in CRAM routines for all materials in [s]
conc_list : list of numpy.ndarray
Concentrations at each of the intermediate points with
the final concentration as the last element
op_results : list of openmc.deplete.OperatorResult
Eigenvalue and reaction rates from intermediate transport
simulations
"""
# Step 1: deplete with matrix 1/2*A(y0)
time1, conc_eos1 = timed_deplete(
self.chain, bos_conc, bos_rates, dt, matrix_func=cf4_f1)
res1 = self.operator(conc_eos1, power)

# Step 2: deplete with matrix 1/2*A(y1)
time2, conc_eos2 = timed_deplete(
self.chain, bos_conc, res1.rates, dt, matrix_func=cf4_f1)
res2 = self.operator(conc_eos2, power)

# Step 3: deplete with matrix -1/2*A(y0)+A(y2)
list_rates = list(zip(bos_rates, res2.rates))
time3, conc_eos3 = timed_deplete(
self.chain, conc_eos1, list_rates, dt, matrix_func=cf4_f2)
res3 = self.operator(conc_eos3, power)

# Step 4: deplete with two matrix exponentials
list_rates = list(zip(bos_rates, res1.rates, res2.rates, res3.rates))
time4, conc_inter = timed_deplete(
self.chain, bos_conc, list_rates, dt, matrix_func=cf4_f3)
time5, conc_eos5 = timed_deplete(
self.chain, conc_inter, list_rates, dt, matrix_func=cf4_f4)

return (time1 + time2 + time3 + time4 + time5,
[conc_eos1, conc_eos2, conc_eos3, conc_eos5],
[res1, res2, res3])

[docs]class CELIIntegrator(Integrator):
r"""Deplete using the CE/LI CFQ4 algorithm.

Implements the CE/LI Predictor-Corrector algorithm using the fourth order
commutator-free integrator <https://doi.org/10.1137/05063042>_.

"CE/LI" stands for constant extrapolation on predictor and linear
interpolation on corrector. This algorithm is mathematically defined as:

.. math::
\begin{aligned}
y' &= A(y, t) y(t) \\
A_0 &= A(y_n, t_n) \\
y_p &= \text{expm}(h A_0) y_n \\
A_1 &= A(y_p, t_n + h) \\
y_{n+1} &= \text{expm}(\frac{h}{12} A_0 + \frac{5h}{12} A1)
\text{expm}(\frac{5h}{12} A_0 + \frac{h}{12} A1) y_n
\end{aligned}

Parameters
----------
operator : openmc.deplete.TransportOperator
Operator to perform transport simulations
timesteps : iterable of float
Array of timesteps in units of [s]. Note that values are not
cumulative.
power : float or iterable of float, optional
Power of the reactor in [W]. A single value indicates that
the power is constant over all timesteps. An iterable
indicates potentially different power levels for each timestep.
For a 2D problem, the power can be given in [W/cm] as long
as the "volume" assigned to a depletion material is actually
an area in [cm^2]. Either power or power_density must be
specified.
power_density : float or iterable of float, optional
Power density of the reactor in [W/gHM]. It is multiplied by
initial heavy metal inventory to get total power if power
is not speficied.

Attributes
----------
operator : openmc.deplete.TransportOperator
Operator to perform transport simulations
chain : openmc.deplete.Chain
Depletion chain
timesteps : iterable of float
Size of each depletion interval in [s]
power : iterable of float
Power of the reactor in [W] for each interval in :attr:timesteps
"""
_num_stages = 2

[docs]    def __call__(self, bos_conc, rates, dt, power, _i=None):
"""Perform the integration across one time step

Parameters
----------
bos_conc : numpy.ndarray
Initial concentrations for all nuclides in [atom]
rates : openmc.deplete.ReactionRates
Reaction rates from operator
dt : float
Time in [s] for the entire depletion interval
power : float
Power of the system in [W]
_i : int, optional
Current iteration count. Not used

Returns
-------
proc_time : float
Time spent in CRAM routines for all materials in [s]
conc_list : list of numpy.ndarray
Concentrations at each of the intermediate points with
the final concentration as the last element
op_results : list of openmc.deplete.OperatorResult
Eigenvalue and reaction rates from intermediate transport
simulation
"""
# deplete to end using BOS rates
proc_time, conc_ce = timed_deplete(self.chain, bos_conc, rates, dt)
res_ce = self.operator(conc_ce, power)

# deplete using two matrix exponentials
list_rates = list(zip(rates, res_ce.rates))

time_le1, conc_inter = timed_deplete(
self.chain, bos_conc, list_rates, dt, matrix_func=celi_f1)

time_le2, conc_end = timed_deplete(
self.chain, conc_inter, list_rates, dt, matrix_func=celi_f2)

return proc_time + time_le1 + time_le1, [conc_ce, conc_end], [res_ce]

[docs]class EPCRK4Integrator(Integrator):
r"""Deplete using the EPC-RK4 algorithm.

Implements an extended predictor-corrector algorithm with traditional
Runge-Kutta 4 method. This algorithm is mathematically defined as:

.. math::
\begin{aligned}
F_1 &= h A(y_0) \\
y_1 &= \text{expm}(1/2 F_1) y_0 \\
F_2 &= h A(y_1) \\
y_2 &= \text{expm}(1/2 F_2) y_0 \\
F_3 &= h A(y_2) \\
y_3 &= \text{expm}(F_3) y_0 \\
F_4 &= h A(y_3) \\
y_4 &= \text{expm}(1/6 F_1 + 1/3 F_2 + 1/3 F_3 + 1/6 F_4) y_0
\end{aligned}

Parameters
----------
operator : openmc.deplete.TransportOperator
Operator to perform transport simulations
timesteps : iterable of float
Array of timesteps in units of [s]. Note that values are not
cumulative.
power : float or iterable of float, optional
Power of the reactor in [W]. A single value indicates that
the power is constant over all timesteps. An iterable
indicates potentially different power levels for each timestep.
For a 2D problem, the power can be given in [W/cm] as long
as the "volume" assigned to a depletion material is actually
an area in [cm^2]. Either power or power_density must be
specified.
power_density : float or iterable of float, optional
Power density of the reactor in [W/gHM]. It is multiplied by
initial heavy metal inventory to get total power if power
is not speficied.

Attributes
----------
operator : openmc.deplete.TransportOperator
Operator to perform transport simulations
chain : openmc.deplete.Chain
Depletion chain
timesteps : iterable of float
Size of each depletion interval in [s]
power : iterable of float
Power of the reactor in [W] for each interval in :attr:timesteps
"""
_num_stages = 4

[docs]    def __call__(self, conc, rates, dt, power, _i=None):
"""Perform the integration across one time step

Parameters
----------
conc : numpy.ndarray
Initial concentrations for all nuclides in [atom]
rates : openmc.deplete.ReactionRates
Reaction rates from operator
dt : float
Time in [s] for the entire depletion interval
power : float
Power of the system in [W]
_i : int, optional
Current depletion step index, unused.

Returns
-------
proc_time : float
Time spent in CRAM routines for all materials in [s]
conc_list : list of numpy.ndarray
Concentrations at each of the intermediate points with
the final concentration as the last element
op_results : list of openmc.deplete.OperatorResult
Eigenvalue and reaction rates from intermediate transport
simulations
"""

# Step 1: deplete with matrix A(y0) / 2
time1, conc1 = timed_deplete(
self.chain, conc, rates, dt, matrix_func=rk4_f1)
res1 = self.operator(conc1, power)

# Step 2: deplete with matrix A(y1) / 2
time2, conc2 = timed_deplete(
self.chain, conc, res1.rates, dt, matrix_func=rk4_f1)
res2 = self.operator(conc2, power)

# Step 3: deplete with matrix A(y2)
time3, conc3 = timed_deplete(
self.chain, conc, res2.rates, dt)
res3 = self.operator(conc3, power)

# Step 4: deplete with matrix built from weighted rates
list_rates = list(zip(rates, res1.rates, res2.rates, res3.rates))
time4, conc4 = timed_deplete(
self.chain, conc, list_rates, dt, matrix_func=rk4_f4)

return (time1 + time2 + time3 + time4, [conc1, conc2, conc3, conc4],
[res1, res2, res3])

[docs]class LEQIIntegrator(Integrator):
r"""Deplete using the LE/QI CFQ4 algorithm.

Implements the LE/QI Predictor-Corrector algorithm using the fourth order
commutator-free integrator <https://doi.org/10.1137/05063042>_.

"LE/QI" stands for linear extrapolation on predictor and quadratic
interpolation on corrector. This algorithm is mathematically defined as:

.. math::
\begin{aligned}
y' &= A(y, t) y(t) \\
A_{last} &= A(y_{n-1}, t_n - h_1) \\
A_0 &= A(y_n, t_n) \\
F_1 &= \frac{-h_2^2}{12h_1} A_{last} + \frac{h_2(6h_1+h_2)}{12h_1} A_0 \\
F_2 &= \frac{-5h_2^2}{12h_1} A_{last} + \frac{h_2(6h_1+5h_2)}{12h_1} A_0 \\
y_p &= \text{expm}(F_2) \text{expm}(F_1) y_n \\
A_1 &= A(y_p, t_n + h_2) \\
F_3 &= \frac{-h_2^3}{12 h_1 (h_1 + h_2)} A_{last} +
\frac{h_2 (5 h_1^2 + 6 h_2 h_1 + h_2^2)}{12 h_1 (h_1 + h_2)} A_0 +
\frac{h_2 h_1)}{12 (h_1 + h_2)} A_1 \\
F_4 &= \frac{-h_2^3}{12 h_1 (h_1 + h_2)} A_{last} +
\frac{h_2 (h_1^2 + 2 h_2 h_1 + h_2^2)}{12 h_1 (h_1 + h_2)} A_0 +
\frac{h_2 (5 h_1^2 + 4 h_2 h_1)}{12 h_1 (h_1 + h_2)} A_1 \\
y_{n+1} &= \text{expm}(F_4) \text{expm}(F_3) y_n
\end{aligned}

It is initialized using the CE/LI algorithm.

Parameters
----------
operator : openmc.deplete.TransportOperator
Operator to perform transport simulations
timesteps : iterable of float
Array of timesteps in units of [s]. Note that values are not
cumulative.
power : float or iterable of float, optional
Power of the reactor in [W]. A single value indicates that
the power is constant over all timesteps. An iterable
indicates potentially different power levels for each timestep.
For a 2D problem, the power can be given in [W/cm] as long
as the "volume" assigned to a depletion material is actually
an area in [cm^2]. Either power or power_density must be
specified.
power_density : float or iterable of float, optional
Power density of the reactor in [W/gHM]. It is multiplied by
initial heavy metal inventory to get total power if power
is not speficied.

Attributes
----------
operator : openmc.deplete.TransportOperator
Operator to perform transport simulations
chain : openmc.deplete.Chain
Depletion chain
timesteps : iterable of float
Size of each depletion interval in [s]
power : iterable of float
Power of the reactor in [W] for each interval in :attr:timesteps
"""
_num_stages = 2

[docs]    def __call__(self, bos_conc, bos_rates, dt, power, i):
"""Perform the integration across one time step

Parameters
----------
conc : numpy.ndarray
Initial concentrations for all nuclides in [atom]
rates : openmc.deplete.ReactionRates
Reaction rates from operator
dt : float
Time in [s] for the entire depletion interval
power : float
Power of the system in [W]
i : int
Current depletion step index

Returns
-------
proc_time : float
Time spent in CRAM routines for all materials in [s]
conc_list : list of numpy.ndarray
Concentrations at each of the intermediate points with
the final concentration as the last element
op_results : list of openmc.deplete.OperatorResult
Eigenvalue and reaction rates from intermediate transport
simulation
"""
if i == 0:
if self._i_res < 1:  # need at least previous transport solution
self._prev_rates = bos_rates
return CELIIntegrator.__call__(
self, bos_conc, bos_rates, dt, power, i)
prev_res = self.operator.prev_res[-2]
prev_dt = self.timesteps[i] - prev_res.time[0]
self._prev_rates = prev_res.rates[0]
else:
prev_dt = self.timesteps[i - 1]

# Remaining LE/QI
bos_res = self.operator(bos_conc, power)

le_inputs = list(zip(
self._prev_rates, bos_res.rates, repeat(prev_dt), repeat(dt)))

time1, conc_inter = timed_deplete(
self.chain, bos_conc, le_inputs, dt, matrix_func=leqi_f1)
time2, conc_eos0 = timed_deplete(
self.chain, conc_inter, le_inputs, dt, matrix_func=leqi_f2)

res_inter = self.operator(conc_eos0, power)

qi_inputs = list(zip(
self._prev_rates, bos_res.rates, res_inter.rates,
repeat(prev_dt), repeat(dt)))

time3, conc_inter = timed_deplete(
self.chain, bos_conc, qi_inputs, dt, matrix_func=leqi_f3)
time4, conc_eos1 = timed_deplete(
self.chain, conc_inter, qi_inputs, dt, matrix_func=leqi_f4)

# store updated rates
self._prev_rates = copy.deepcopy(bos_res.rates)

return (
time1 + time2 + time3 + time4, [conc_eos0, conc_eos1],
[bos_res, res_inter])

[docs]class SICELIIntegrator(SIIntegrator):
r"""Deplete using the SI-CE/LI CFQ4 algorithm.

Implements the stochastic implicit CE/LI predictor-corrector algorithm
using the fourth order commutator-free integrator
<https://doi.org/10.1137/05063042>_.

Detailed algorithm can be found in section 3.2 in Colin Josey's thesis
<http://hdl.handle.net/1721.1/113721>_.

Parameters
----------
operator : openmc.deplete.TransportOperator
The operator object to simulate on.
timesteps : iterable of float
Array of timesteps in units of [s]. Note that values are not
cumulative.
power : float or iterable of float, optional
Power of the reactor in [W]. A single value indicates that
the power is constant over all timesteps. An iterable
indicates potentially different power levels for each timestep.
For a 2D problem, the power can be given in [W/cm] as long
as the "volume" assigned to a depletion material is actually
an area in [cm^2]. Either power or power_density must be
specified.
power_density : float or iterable of float, optional
Power density of the reactor in [W/gHM]. It is multiplied by
initial heavy metal inventory to get total power if power
is not speficied.
n_steps : int, optional
Number of stochastic iterations per depletion interval.
Must be greater than zero. Default : 10

Attributes
----------
operator : openmc.deplete.TransportOperator
Operator to perform transport simulations
chain : openmc.deplete.Chain
Depletion chain
timesteps : iterable of float
Size of each depletion interval in [s]
power : iterable of float
Power of the reactor in [W] for each interval in :attr:timesteps
n_steps : int
Number of stochastic iterations per depletion interval
"""
_num_stages = 2

[docs]    def __call__(self, bos_conc, bos_rates, dt, power, _i=None):
"""Perform the integration across one time step

Parameters
----------
bos_conc : numpy.ndarray
Initial bos_concentrations for all nuclides in [atom]
bos_rates : openmc.deplete.ReactionRates
Reaction rates from operator
dt : float
Time in [s] for the entire depletion interval
power : float
Power of the system in [W]
_i : int, optional
Current depletion step index. Not used

Returns
-------
proc_time : float
Time spent in CRAM routines for all materials in [s]
bos_conc_list : list of numpy.ndarray
Concentrations at each of the intermediate points with
the final bos_concentration as the last element
op_results : list of openmc.deplete.OperatorResult
Eigenvalue and reaction rates from intermediate transport
simulations
"""
proc_time, eos_conc = timed_deplete(
self.chain, bos_conc, bos_rates, dt)
inter_conc = copy.deepcopy(eos_conc)

# Begin iteration
for j in range(self.n_steps + 1):
inter_res = self.operator(inter_conc, power)

if j <= 1:
res_bar = copy.deepcopy(inter_res)
else:
rates = 1/j * inter_res.rates + (1 - 1 / j) * res_bar.rates
k = 1/j * inter_res.k + (1 - 1 / j) * res_bar.k
res_bar = OperatorResult(k, rates)

list_rates = list(zip(bos_rates, res_bar.rates))
time1, inter_conc = timed_deplete(
self.chain, bos_conc, list_rates, dt, matrix_func=celi_f1)
time2, inter_conc = timed_deplete(
self.chain, inter_conc, list_rates, dt, matrix_func=celi_f2)
proc_time += time1 + time2

# end iteration
return proc_time, [eos_conc, inter_conc], [res_bar]

[docs]class SILEQIIntegrator(SIIntegrator):
r"""Deplete using the SI-LE/QI CFQ4 algorithm.

Implements the Stochastic Implicit LE/QI Predictor-Corrector algorithm
using the fourth order commutator-free integrator
<https://doi.org/10.1137/05063042>_.

Detailed algorithm can be found in Section 3.2 in Colin Josey's thesis
<http://hdl.handle.net/1721.1/113721>_.

Parameters
----------
operator : openmc.deplete.TransportOperator
The operator object to simulate on.
timesteps : iterable of float
Array of timesteps in units of [s]. Note that values are not
cumulative.
power : float or iterable of float, optional
Power of the reactor in [W]. A single value indicates that
the power is constant over all timesteps. An iterable
indicates potentially different power levels for each timestep.
For a 2D problem, the power can be given in [W/cm] as long
as the "volume" assigned to a depletion material is actually
an area in [cm^2]. Either power or power_density must be
specified.
power_density : float or iterable of float, optional
Power density of the reactor in [W/gHM]. It is multiplied by
initial heavy metal inventory to get total power if power
is not speficied.
n_steps : int, optional
Number of stochastic iterations per depletion interval.
Must be greater than zero. Default : 10

Attributes
----------
operator : openmc.deplete.TransportOperator
Operator to perform transport simulations
chain : openmc.deplete.Chain
Depletion chain
timesteps : iterable of float
Size of each depletion interval in [s]
power : iterable of float
Power of the reactor in [W] for each interval in :attr:timesteps
n_steps : int
Number of stochastic iterations per depletion interval
"""
_num_stages = 2

[docs]    def __call__(self, bos_conc, bos_rates, dt, power, i):
"""Perform the integration across one time step

Parameters
----------
bos_conc : list of numpy.ndarray
Initial concentrations for all nuclides in [atom] for
all depletable materials
bos_rates : list of openmc.deplete.ReactionRates
Reaction rates from operator for all depletable materials
dt : float
Time in [s] for the entire depletion interval
power : float
Power of the system in [W]
i : int
Current depletion step index

Returns
-------
proc_time : float
Time spent in CRAM routines for all materials in [s]
conc_list : list of numpy.ndarray
Concentrations at each of the intermediate points with
the final concentration as the last element
op_results : list of openmc.deplete.OperatorResult
Eigenvalue and reaction rates from intermediate transport
simulation
"""
if i == 0:
if self._i_res < 1:
self._prev_rates = bos_rates
# Perform CELI for initial steps
return SICELIIntegrator.__call__(
self, bos_conc, bos_rates, dt, power, i)
prev_res = self.operator.prev_res[-2]
prev_dt = self.timesteps[i] - prev_res.time[0]
self._prev_rates = prev_res.rates[0]
else:
prev_dt = self.timesteps[i - 1]

# Perform remaining LE/QI
inputs = list(zip(self._prev_rates, bos_rates,
repeat(prev_dt), repeat(dt)))
proc_time, inter_conc = timed_deplete(
self.chain, bos_conc, inputs, dt, matrix_func=leqi_f1)
time1, eos_conc = timed_deplete(
self.chain, inter_conc, inputs, dt, matrix_func=leqi_f2)

proc_time += time1
inter_conc = copy.deepcopy(eos_conc)

for j in range(self.n_steps + 1):
inter_res = self.operator(inter_conc, power)

if j <= 1:
res_bar = copy.deepcopy(inter_res)
else:
rates = 1 / j * inter_res.rates + (1 - 1 / j) * res_bar.rates
k = 1 / j * inter_res.k + (1 - 1 / j) * res_bar.k
res_bar = OperatorResult(k, rates)

inputs = list(zip(self._prev_rates, bos_rates, res_bar.rates,
repeat(prev_dt), repeat(dt)))
time1, inter_conc = timed_deplete(
self.chain, bos_conc, inputs, dt, matrix_func=leqi_f3)
time2, inter_conc = timed_deplete(
self.chain, inter_conc, inputs, dt, matrix_func=leqi_f4)
proc_time += time1 + time2

return proc_time, [eos_conc, inter_conc], [res_bar]