Subroutine Type

Utility/Data Access

Definition

Uses the AKIMA spline fitting method to return the interpolated value or n-th derivative of the interpolated value for a Reference_Spline element.

Use

The AKISPL function can be called by any user-defined subroutine.

Calling Syntax

Fortran

CALL AKISPL (XVAL, ZVAL, ID, IORD, ARRAY, ERRFLG)

C

c_akispl(xval, zval, id, iord, array, errflg)

Python

[value, eflag] = py_akispl(x, z, id, iord)

MATLAB

[value, eflag] = m_akispl(x, z, id, iord)

Input Arguments

[integer] ID

The identifier of the corresponding user defined Reference_Spline element.

[double precision] XVAL

The independent x value at which the AKIMA spline function is supposed to interpolate the output value.

[double precision] ZVAL

The independent z value at which the AKIMA spline function is supposed to interpolate the output value in a 3-D Spline data

[logical] IORD

The order of derivative returned by the AKISPLINE function

Output Values

[double precision] ARRAY

The vector output value of dimension 3.

If IORD is 0, then the returned values are the interpolated values of y.

If IORD is 1, then the returned values are the derivatives of y with respect to x and z.

If IORD is 2, then the output array contains the second derivatives of y with respect to xx, xz, and zz, respectively.

[logical] ERRFLG

The logical variable that is returned to the calling subroutine and that indicates the success of the AKYSPL function call.