d4.02.02 sd_function data structures

Summary:

The types of sd_function concepts represent functions (in the mathematical sense of the term) of one or two variables.

Functions have real values, function_C have complex values. In the rest of this document, we will only talk about functions with real values (function), knowing that everything can be transposed to function_C.

A function is by nature « tabulated »: that is to say that it is only known at certain points. In this case, its evaluation may require interpolation or extrapolation.

A formula is « interpreted »: its representation (data structure) then contains the mathematical expression of the function.

Note:

A formula can be tabulated (for certain values of its variable) by the command CALC_FONC_INTERP. For a tabulated function, the evaluation at a point different from the tabulation points can be done by interpolation or extrapolation. A formula can have as many variables as needed. In contrast, tabulated functions can only have \(\mathrm{0,}1\) or \(2\) variables. We will then speak of « constant function », « function » or « sheet ». The variables of a function (like its result) are « typed »: “TEMP”, “INST”, “EPSI”,… We will then talk about the name of the parameters and the result.

Table of Contents

• 1. Data structure
• 2. Basic object content
  • 2.1. Purpose. PROL
  • 2.2. Subject ». PARA »
  • 2.3. Subject ». VALE »
  • 2.4. Subject ». NOVA »
• 3. Examples
  • 3.1. Constant function: f1
  • 3.2. Real tabulated function: f2
  • 3.3. Complex tabulated function: f3
  • 3.4. Real tablecloth defined by functions: nap1
  • 3.5. Real tablecloth defined by functions: nap2
  • 3.6. Formula function with 1 variable: ff1
  • 3.7. Formula function with 2 variables: ff2
  • 3.8. Formula with 1 variables: ff3 tabulated later
  • 3.9. Function tabulated from another function