Method for deriving a piecewise linear model

A method executed by a computer for creating a piecewise-linear model of an integrated circuit, comprising the steps of:

• observing an independent variable that is independent of a physical process and a dependent variable that is dependent on said physical process during design of the integrated circuit to determine a plurality of observed values of said independent variable and a plurality of observed values of said dependent variable;
• plotting said plurality of observed values of said independent variable against said plurality of observed values of said dependent variable;
• connecting a first chord between a lowest observed value of said dependent variable and a highest observed value of said dependent variable to create a piecewise-linear model;
• determining a first error value between a plurality of computed values of said dependent variable based on said first chord and each of said plurality of observed values of said dependent variable that are located between said lowest and highest observed values of said dependent variable;
• comparing said first error values against a predetermined tolerance;
• and
• placing a first breakpoint at a midway point of said plurality of observed values of said dependent variable if one of said first error values is greater than said predetermined tolerance to form a second chord between said lowest observed value of said dependent variable and said first breakpoint and a third chord between said first breakpoint and said highest observed value of said dependent variable.