Subroutine Type

Utility/General

Definition

Evaluates a CHEBYSHEV polynomial function.

Use

This function can be called by any user-defined subroutine.

Calling Syntax

Fortran

CALL CHEBY(X, X0, PAR, NPAR, IORD, VALUE, ERRFLG)

C

c_cheby(x, x0, par, npar, iord, value, errflg)

Python

[value, errflg] = py_cheby(x, x0, par, npar, iord)

MATLAB

[value, errflg] = m_cheby(x, x0, par, npar, iord)

Input Arguments

X [double precision]

The independent variable.  For example, to specify time as the independent variable, specify X as TIME.

X0 [double precision]

The phase shift in the Chebychev polynomial.

PAR [double precision]

The array of coefficients.

NPAR [integer]

The number of coefficients specified.

IORD [integer]

The order of the derivative that CHEBY has to return.  Order can be 0, 1 or 2.

Output Values

Value [integer]

The value that the subroutine returns.

Errflg [logical]

A logical (true or false) variable that CHEBY returns to the calling subroutine.  If CHEBY detects an error while calling the subroutine, it sets the error flag to true.