def annlinit(model, abstol=1.0e-3, reltol=1.0e-3, nsteps = 20000, itermaxstep = None):
"""
annlinit initializes the environment for simulations using CVODE
INPUT:
-------
model: a PySB model object
abstol: absolute tolerance for CVODE integrator
reltol: relative tolerance for CVODE integrator
nsteps: number of time steps of integration (depends on the units of the parameters)
itermaxstep: maximum number of iteration steps
OUTPUT:
-------
a list object containing:
[f, rhs_exprs, y, odesize, data, xout, yout, nsteps, cvode_mem, yzero, reltol, abstol]
f: the function called by cvodes calls that returns dy
rhs_exprs: the python expression for the right hand side (list of strings)
y: a CVode NVector object with the initial values for all species
odesize: the number of odes
data: a ctypes data structure (for Sundials) containing the parameter values (floats)
xout: the numpy array where the time values will be put
yout: the numpy array where the integrated timeseries will be put
nsteps: the number of time steps
cvode_mem: cvode memory object defining the step method
yzero: a numpy array of the initial conditions
paramarray: a numpy array containing the parameter values (floats). (same contents as data, but different datatype)
reltol: integrator relative tolerance (float)
abstol: integrator absolute tolerance (float)
paramarray, a parameter array
"""
# Generate equations
pysb.bng.generate_equations(model)
odesize = len(model.odes)
yzero = numpy.zeros(odesize) #initial values for yzero
# assign the initial conditions
for cplxptrn, ic_param in model.initial_conditions:
speci = model.get_species_index(cplxptrn)
yzero[speci] = ic_param.value
# initialize y with the yzero values
y = cvode.NVector(yzero)
# make a dict of ydot functions. notice the functions are in this namespace.
# replace the kxxxx constants with elements from the params array
rhs_exprs = []
for i in range(0,odesize):
# get the function string from sympy, replace the the "sN" with y[N]
tempstring = re.sub(r's(\d+)', lambda m: 'y[%s]'%(int(m.group(1))), str(model.odes[i]))
# replace the constants with 'p' array names; cycle through the whole list
for j, parameter in enumerate(model.parameters):
tempstring = re.sub('(?<![A-Za-z0-9_])%s(?![A-Za-z0-9_])' % parameter.name, 'p[%d]' % j, tempstring)
# make a list of compiled rhs expressions which will be run by the integrator
# use the ydots to build the function for analysis
# (second arg is the "filename", useful for exception/debug output)
rhs_exprs.append(compile(tempstring, '<ydot[%s]>' % i, 'eval'))
# Create a generic "p" array to hold the parameters when calling the function
numparams = len(model.parameters)
class UserData(ctypes.Structure):
_fields_ = [('p', cvode.realtype*numparams)] # parameters
PUserData = ctypes.POINTER(UserData)
data = UserData()
# Create the paramarray to hold the parameters and pass them from C to Python
# FIXME: could prob do this directly from data.p
data.p[:] = [p.value for p in model.parameters]
paramarray = numpy.array([p.value for p in model.parameters])
# allocate "p" as a pointer array that can be called by sundials "f" as needed
def f(t, y, ydot, f_data):
data = ctypes.cast(f_data, PUserData).contents
rhs_locals = {'y': y, 'p': data.p}
for i in range(0,len(model.odes)):
ydot[i] = eval(rhs_exprs[i], rhs_locals)
return 0
# initialize the cvode memory object, use BDF and Newton for stiff
cvode_mem = cvode.CVodeCreate(cvode.CV_BDF, cvode.CV_NEWTON)
# allocate the cvode memory as needed, pass the function and the initial ys
cvode.CVodeMalloc(cvode_mem, f, 0.0, y, cvode.CV_SS, reltol, abstol)
# point the parameters to the correct array
cvode.CVodeSetFdata(cvode_mem, ctypes.pointer(data))
# link integrator with linear solver
cvode.CVDense(cvode_mem, odesize)
# maximum iteration steps
if itermaxstep != None:
cvode.CVodeSetMaxStep(cvode_mem, itermaxstep)
#list of outputs
xout = numpy.zeros(nsteps)
yout = numpy.zeros([nsteps, odesize])
#initialize the arrays
xout[0] = 0.0 # FIXME: this assumes that the integration starts at zero... CHANGE IF NEEDED
#first step in yout
for i in range(0, odesize):
yout[0][i] = y[i]
# f: the function called by cvodes calls that returns dy
# rhs_exprs: the python expression for the right hand side (list of strings)
# y: a CVode NVector object with the initial values for all species
# odesize: the number of odes
# data: a ctypes data structure (for Sundials) containing the parameter values (floats)
# xout: the numpy array where the time values will be put
# yout: the numpy array where the integrated timeseries will be put
# nsteps: the number of time steps
# cvode_mem: cvode memory object defining the step method
# yzero: a numpy array of the initial conditions
# paramarray: a numpy array containing the parameter values (floats). (same contents as data, but different datatype)
# reltol: integrator relative tolerance (float)
# abstol: integrator absolute tolerance (float)
return [f, rhs_exprs, y, odesize, data, xout, yout, nsteps, cvode_mem, yzero, reltol, abstol], paramarray
def odeinit(model,
reltol=1.0e-3,
abstol=1.0e-3,
nsteps=1000,
itermaxstep=None):
'''
must be run to set up the environment for annealing with pysundials
'''
# Generate equations
pysb.bng.generate_equations(model)
# Get the size of the ODE array
odesize = len(model.odes)
# init the arrays we need
yzero = numpy.zeros(odesize) #initial values for yzero
# assign the initial conditions
for cplxptrn, ic_param in model.initial_conditions:
speci = model.get_species_index(cplxptrn)
yzero[speci] = ic_param.value
# initialize y with the yzero values
y = cvode.NVector(yzero)
# make a dict of ydot functions. notice the functions are in this namespace.
# replace the kxxxx constants with elements from the params array
rhs_exprs = []
for i in range(0, odesize):
# first get the function string from sympy, replace the the "sN" with y[N]
tempstring = re.sub(r's(\d+)', lambda m: 'y[%s]' % (int(m.group(1))),
str(model.odes[i]))
# now replace the constants with 'p' array names; cycle through the whole list
#for j in range(0, numparams):
# tempstring = re.sub('(?<![A-Za-z0-9_])%s(?![A-Za-z0-9_])'%(model.parameters[j].name),'p[%d]'%(j), tempstring)
for j, parameter in enumerate(model.parameters):
tempstring = re.sub(
'(?<![A-Za-z0-9_])%s(?![A-Za-z0-9_])' % parameter.name,
'p[%d]' % j, tempstring)
# make a list of compiled rhs expressions which will be run by the integrator
# use the ydots to build the function for analysis
# (second arg is the "filename", useful for exception/debug output)
rhs_exprs.append(compile(tempstring, '<ydot[%s]>' % i, 'eval'))
# Create the structure to hold the parameters when calling the function
# This results in a generic "p" array
numparams = len(model.parameters)
class UserData(ctypes.Structure):
_fields_ = [('p', cvode.realtype * numparams)] # parameters
PUserData = ctypes.POINTER(UserData)
data = UserData()
data.p[:] = [p.value for p in model.parameters]
paramarray = numpy.array([p.value for p in model.parameters])
# allocate the "p" array as a pointer array that can be called by sundials "f" as needed
def f(t, y, ydot, f_data):
data = ctypes.cast(f_data, PUserData).contents
rhs_locals = {'y': y, 'p': data.p}
for i in range(0, len(model.odes)):
ydot[i] = eval(rhs_exprs[i], rhs_locals)
return 0
# initialize the cvode memory object, use BDF and Newton for stiff systems
cvode_mem = cvode.CVodeCreate(cvode.CV_BDF, cvode.CV_NEWTON)
# allocate the cvode memory as needed, pass the function and the init ys
cvode.CVodeMalloc(cvode_mem, f, 0.0, y, cvode.CV_SS, reltol, abstol)
# point the parameters to the correct array
# if the params are changed later this does not need to be reassigned (???)
cvode.CVodeSetFdata(cvode_mem, ctypes.pointer(data))
# link integrator with linear solver
cvode.CVDense(cvode_mem, odesize)
#stepsize
if itermaxstep != None:
cvode.CVodeSetMaxStep(cvode_mem, itermaxstep)
#list of outputs
xout = numpy.zeros(nsteps)
yout = numpy.zeros([nsteps, odesize])
#initialize the arrays
#print "Initial parameter values:", y
xout[0] = 0.0 #CHANGE IF NEEDED
#first step in yout
for i in range(0, odesize):
yout[0][i] = y[i]
return [
f, rhs_exprs, y, odesize, data, xout, yout, nsteps, cvode_mem, yzero,
reltol, abstol
], paramarray