Initial Conditions ================== DORiE computes transient solutions, and hence needs a solution from which it can start. There are multiple ways of specifying an initial condition. All have in common that the data provided must be interpolated on the respective solution grid function space. Depending on the actual input data, this means that information can be lost and specific features can be distorted. Users are responsible to ensure that the solution grid function space and the input data for initial conditions match in this sense. Initial conditions can generally be stated in several physical quantities, as long as the respective quantity has a unique transformation to the solver solution quantity. Initial condition input is controlled entirely via the :doc:Configuration File . Input Types ----------- This is an overview of all input types for initial conditions. They are controlled by the initial.type key and available for every model. .. object:: Linear Function * type = linear This type of initial condition defines an analytic linear function :math:f(h) which only depends on height :math:h. The user specifies the value at height zero, :math:f_0 = f(h = 0 \, \mathrm{m}), and a gradient :math:\Delta f. The function defining the solution is then given by .. math:: f (h) = f_0 + h \cdot \Delta f .. object:: HDF5_ Dataset * type = data This type of initial condition defines function :math:f(x,y,z) depending on the data included in the datafile initial.datafile and the dataset initial.dataset within the datafile. Values between the centers of the data set are interpolated depending on the keyword initial.interpolator Transformation Types -------------------- This is an overview of the transformation types of all models. They are controlled via the initial.quantity key. Richards ^^^^^^^^ Initial condition tranformations for the Richards solver. .. object:: No Transformation * quantity = matricHead The input data is directly interpreted as matric head :math:h_m [\mathrm{m}]. Interpolators ------------- .. object:: Nearest neighbor interpolator Interprets dataset values as cell values. * interpolation: nearest .. _HDF5: https://www.h5py.org/