CausalKinetiX (version 0.2.1)

ode.solver: ode.solver

Description

Solves a mass-action ODE for a target variable Y by using smooth approximations of the predictor variables X.

Usage

ode.solver(time_vec, initial_value, times, X, model, target, coefs,
  smooth.type = "smoothing.spline", reltol = 10^(-10),
  abstol = 10^(-16))

Arguments

time_vec

numeric vector. Specifices the points at which to evaluate the target trajectory.

initial_value

numeric value. Specifies the value of the target at initial time point.

times

numeric vector of length L. Specifices the time points at which the predictors where observed.

X

predictor matrix of dimension L x d. Each column corresponds to a different predictor observed at the time points times.

model

list of mass-action terms. Each element in the list consists of a vector of predictor variables which are multiplied to a single term in the mass-action equation.

target

integer specifing which variable is the target.

coefs

numeric vector. Specifies the parameter values for each term in model.

smooth.type

string. Specifies which type of smoothing to use. The following options exist: "smoothing.spline", "loess", "linear", "constant".

reltol

numeric. Relative tolarance used in CVODE.

abstol

numeric. Absolute tolarance used in CVODE.

Value

object returned by CVODE.

Details

For further details see the references.

References

Pfister, N., S. Bauer, J. Peters (2018). Identifying Causal Structure in Large-Scale Kinetic Systems ArXiv e-prints (arXiv:1810.11776).

Examples

# NOT RUN {
## Generate data from Maillard reaction
simulation.obj <- generate.data.maillard(target=11,
                                         env=rep(1:5, each=5),
                                         L=20,
                                         par.noise=list(noise.sd=0.1,
                                                        only.target.noise=FALSE,
                                                        relativ=TRUE))
D <- simulation.obj$simulated.data
time <- simulation.obj$time

## Solve for Melanoidin
X <- do.call(cbind, split(as.vector(t(D[1:5,])), rep(1:11, each=length(unique(time)))))
times <- rep(unique(time), 5)
odefit <- ode.solver(time, 0, times, X, list(c(8)), 11, 0.12514)
plot(odefit[,1], odefit[,2], type="l")
points(times, X[,11])
# }