"""
:meta private:
"""
from typing import Optional
from pharmpy.basic import Expr
from pharmpy.deps import sympy
from pharmpy.internals.fs.path import normalize_user_given_path
from pharmpy.model import (
Assignment,
ColumnInfo,
Compartment,
CompartmentalSystem,
CompartmentalSystemBuilder,
DataInfo,
EstimationStep,
ExecutionSteps,
Model,
NormalDistribution,
Parameter,
Parameters,
RandomVariables,
Statements,
output,
)
from .data import add_admid, create_default_datainfo, read_dataset_from_datainfo
from .error import set_proportional_error_model
from .odes import add_bioavailability, set_first_order_absorption
from .parameter_variability import add_iiv, create_joint_distribution
from .parameters import set_initial_estimates
[docs]
def create_basic_pk_model(
administration: str = 'iv',
dataset_path: Optional[str] = None,
cl_init: float = 0.01,
vc_init: float = 1.0,
mat_init: float = 0.1,
) -> Model:
"""
Creates a basic pk model of given type. The model will be a one compartment model, with first
order elimination and in the case of oral administration first order absorption with no absorption
delay. The elimination rate will be :math:`CL/V` and the absorption rate will be :math:`1/MAT`
Parameters
----------
administration : str
Type of PK model to create. Supported are 'iv', 'oral' and 'ivoral'
dataset_path : str
Optional path to a dataset
cl_init : float
Initial estimate of the clearance parameter
vc_init : float
Initial estimate of the central volume parameter
mat_init : float
Initial estimate of the mean absorption time parameter (if applicable)
Return
------
Model
Pharmpy model object
Examples
--------
>>> from pharmpy.modeling import *
>>> model = create_basic_pk_model('oral')
"""
if dataset_path is not None:
dataset_path = normalize_user_given_path(dataset_path)
di = create_default_datainfo(dataset_path)
df = read_dataset_from_datainfo(di, datatype='nonmem')
else:
di_col_dict = {'ID': 'id', 'TIME': 'idv', 'AMT': 'dose', 'DV': 'dv'}
di_ci = [ColumnInfo.create(key, type=value) for key, value in di_col_dict.items()]
di = DataInfo.create(di_ci)
df = None
if administration not in [
'iv',
'oral',
'ivoral',
]:
raise ValueError(f'Invalid input: `{administration}` as administration is not supported.')
pop_cl = Parameter('POP_CL', cl_init, lower=0)
pop_vc = Parameter('POP_VC', vc_init, lower=0)
iiv_cl = Parameter('IIV_CL', 0.1)
iiv_vc = Parameter('IIV_VC', 0.1)
params = Parameters((pop_cl, pop_vc, iiv_cl, iiv_vc))
eta_cl_name = 'ETA_CL'
eta_cl = NormalDistribution.create(eta_cl_name, 'iiv', 0, iiv_cl.symbol)
eta_vc_name = 'ETA_VC'
eta_vc = NormalDistribution.create(eta_vc_name, 'iiv', 0, iiv_vc.symbol)
rvs = RandomVariables.create([eta_cl, eta_vc])
CL = Expr.symbol('CL')
VC = Expr.symbol('VC')
cl_ass = Assignment(CL, pop_cl.symbol * Expr.symbol(eta_cl_name).exp())
vc_ass = Assignment(VC, pop_vc.symbol * Expr.symbol(eta_vc_name).exp())
cb = CompartmentalSystemBuilder()
# FIXME: This shouldn't be used here
from pharmpy.model.external.nonmem.advan import dosing, find_dose
doses = dosing(di, df, 1)
central = Compartment.create('CENTRAL', doses=find_dose(doses, 1))
cb.add_compartment(central)
cb.add_flow(central, output, CL / VC)
ipred = Assignment(Expr.symbol('IPRED'), central.amount / VC)
y_ass = Assignment(Expr.symbol('Y'), ipred.symbol)
stats = Statements([cl_ass, vc_ass, CompartmentalSystem(cb), ipred, y_ass])
est = EstimationStep.create(
"FOCE",
interaction=True,
maximum_evaluations=99999,
predictions=('PRED', 'CIPREDI'),
residuals=('CWRES',),
)
eststeps = ExecutionSteps.create([est])
model = Model.create(
name='start',
statements=stats,
execution_steps=eststeps,
dependent_variables={y_ass.symbol: 1},
random_variables=rvs,
parameters=params,
description='Start model',
dataset=df,
datainfo=di,
)
model = set_proportional_error_model(model)
model = create_joint_distribution(model, [eta_cl_name, eta_vc_name])
if administration == 'oral' or administration == 'ivoral':
model = set_first_order_absorption(model)
model = set_initial_estimates(model, {'POP_MAT': mat_init})
model = add_iiv(model, list_of_parameters='MAT', expression='exp', initial_estimate=0.1)
if administration == 'ivoral':
# FIXME: Dependent on CMT column having 1 and 2 as values otherwise
# compartment structure don't match
model = add_bioavailability(model, logit_transform=True)
model = set_initial_estimates(model, {'POP_BIO': 0.5})
# Add IIV to BIO
# TODO: ? Should there be another initial estimate?
model = add_iiv(model, list_of_parameters="BIO", expression='add', initial_estimate=0.1)
# Set dosing to the CENTRAL compartment as well
ode = model.statements.ode_system
cb = CompartmentalSystemBuilder(ode)
if df is None:
doses = dosing(di, df, 2)
central_dose = find_dose(doses, comp_number=2, admid=2)
else:
# doses = dosing(di, df, 1)
central_dose = find_dose(doses, comp_number=2, admid=2)
if not central_dose:
raise ValueError(
(
"Could not determine IV dose from dataset. "
"Currently require CMT column with values 1 and 2 "
)
)
cb.set_dose(cb.find_compartment("CENTRAL"), dose=central_dose)
ode = CompartmentalSystem(cb)
model = model.replace(
statements=model.statements.before_odes + ode + model.statements.after_odes
)
if df is not None:
model = add_admid(model)
# Change bioavailability to piecewise for oral/iv doses
model = model.replace(
statements=model.statements.reassign(
Expr.symbol("F_BIO"),
Expr.piecewise(
(
1 / (1 + ((-Expr.symbol("BIO")).exp())),
sympy.Eq(sympy.Symbol('ADMID'), 1),
),
(1, sympy.true),
),
)
)
# Add covariate to error model with the following logic
# RUV = 1 * covariate
# Y = F + F*EPS*RUV
ruv_ass = Assignment(Expr.symbol("RUV"), Expr.integer(1))
model = model.replace(
statements=model.statements.before_odes
+ ruv_ass
+ model.statements.ode_system
+ model.statements.after_odes
)
Y_ass = model.statements.find_assignment("Y")
ipred = Y_ass.expression.make_args(Y_ass.expression)[0]
error = Y_ass.expression.make_args(Y_ass.expression)[1]
new_Y_ass = Assignment.create(Y_ass.symbol, ipred + error * ruv_ass.symbol)
model = model.replace(
statements=model.statements.reassign(Y_ass.symbol, new_Y_ass.expression)
)
return model
