Parameter File

The parameter file ($DIR/parameters.def; see Figure 9) assigns the desired numerical values to all of the parameters characterizing the human cardiovascular model and its execution. The syntax for parameter assignment must be precisely as written within the following squiggly brackets: { parameter: numerical_value}. Otherwise, the parameters will not be read in properly. The parameter file also includes definitions of each of the parameters and default or nominal parameter values. Each line containing these definitions and default values as well as any other comments must be preceded by a %. Parameter assignments should never be preceded by a %, else they will not be read in properly. Each of the parameters in the file may be updated in the midst of a simulation period with the exception of those labelled with {*}. Any update to these parameters will simply be ignored.

  

Figure 9: The $DIR/parameters.def file which contains the parameter values characterizing the human cardiovascular model of Section 2 and its execution.

The parameter file consists of integration and sampling parameters; display parameters; status parameters; pulsatile heart and circulation parameters; short-term regulatory system parameters, and resting physiologic perturbation parameters. The status parameters are flags which indicate the preparation of the pulsatile heart and circulation to be implemented as well as whether a particular short-term regulatory system or resting physiologic perturbation is to be activated or deactivated. The status parameters, which cannot be adjusted in the midst of a simulation period, override any of the other relevant parameters assignments. For example, if dra is set to zero, then the exogenous disturbance to $R_a$ is deactivated and may not be activated during the simulation period regardless of the value assigned to stdwr, which establishes the standard deviation of the disturbance to $R_a$. Note that a short-term regulatory system or resting physiologic perturbation may also be deactivated through the parameters that characterize them. For example, the exogenous disturbance to $R_a$ may be deactivated by setting stdwr to zero. In this case, the exogenous disturbance to $R_a$ may be subsequently activated during the simulation period by setting stdwr to a value greater than zero. However, if the researcher knows that a short-term regulatory system or resting physiologic perturbation is not required for his simulation, then the appropriate status parameter should be deactivated for the purposes of increasing execution speed. Note that the pulsatile heart and circulation parameters may be applicable to the intact circulation, heart-lung unit, and/or systemic circulation preparations and are labelled accordingly.