Subroutine Type

Utility/Data Access

Definition

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

Use

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

Calling Syntax

Fortran

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

C

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

Python

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

MATLAB

[value, eflag] = m_cubspl(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 cubic spline function is supposed to interpolate the output value.

[double precision] ZVAL

The independent z value at which the cubic spline function is supposed to interpolate the output value for a 3-D spline data.

[logical] IORD

The order of derivative returned by the CUBSPL function.

Output Values

[double precision] ARRAY

The vector output value of dimension 3 that contains the computed interpolated value y (for IORD equal to 0).

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 arrays contains the second derivatives of dy in dx2, dxdz, and dz2, respectively.

[logical] ERRFLG

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