conv_flux_forward_difference.m File Reference

function computing the derivative of a convective flux by forward difference. More...

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Functions
function [ flux_lin , lambda ] =	conv_flux_forward_difference (glob, U, params)
	function computing the derivative of a convective flux by forward difference. More...

Detailed Description

function computing the derivative of a convective flux by forward difference.

Definition in file conv_flux_forward_difference.m.

Function Documentation

function [ flux_lin , lambda ] = conv_flux_forward_difference	(		glob,
			U,
			params
	)

function computing the derivative of a convective flux by forward difference.

Convective flux functions are used e.g. by finite folume operators like fv_operators_conv_explicit_lax_friedrichs() or fv_num_conv_flux_engquist_osher().

Parameters

glob	a matrix of row vectors for each coordinate dimension of the grid defining the coordinates where the flux function is evaluated, in case it is space dependent, i.e. we have something like \(f(u,x)\).
U	a vector with evaluations of a solution \(u\) which are passed as an argument to the flux function \(f\)
params	a structure with model parameters

Return values

flux_lin	is a matrix which row entries represent the velocity vectors in the edge midpoints.
lambda	is a bound such that \[\lambda \cdot \sup_u n_{jl} \cdot f'(u) \leq 1\] e.g. \(\lambda := \frac{1}{\sup|v(x,y)|}\) for \(f(u) = v \cdot u\). This is value only reasonable in decomp_mode==0, otherwise an empty variable is returned.

Required fields of params:

• debug —  flag indicating wether debug output shall be turned on
• conv_flux_ptr —  the convective flux function \(f : \mathbb{R} \to \mathbb{R}^d\) of which the derivative shall be computed.

dummy

Definition at line 17 of file conv_flux_forward_difference.m.

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