Welcome to Adams/Solver Subroutines - Kxcad.net

14
Adams/Solver
Input Arguments
xval A double-precision value that specifies the x value at which AKISPL is
to interpolate y.
zval A double-precision value that specifies the z value at which AKISPL is
to interpolate y.
id An integer variable that specifies the identifier of the corresponding
SPLINE statement.
iord An integer variable that specifies the order of the derivative that AKISPL
is to return. The order is usually zero, but it can be one or two.
Output Arguments
array A double-precision array of length three. If iord equals zero, array(1)
returns the value of y that AKISPL calculates. If iord equals one, array
returns:
Extended Definition
∂ y
-----
∂ x
2
y
∂
∂ 2 ------x
AKISPL accesses data in a SPLINE statement (C++ or FORTRAN), using the Akima cubic-curve fitting
method to fit a spline to the data (that is, to add interpolated points), and returns one of the following:
• A value for the dependent variable (y) for each value it receives for the independent variable or
variables.
• The first partial derivatives of the dependent variable.
and , respectively. If iord equals two, array returns:
Note that:
∂ y-----
∂ z
2
y
∂
-----------
∂ x∂ z
2
y
∂
∂ 2 -----z
, , and , respectively.
2
y
∂ ∂
----------- =
-----------
∂ z∂ x ∂ x∂ z
errflg A logical (true or false) variable that AKISPL returns to the calling
subroutine. If AKISPL detects an error in its calculations, it sets errflg to
true before it returns errflg to the calling subroutine.
• The second partial derivatives of the dependent variable.
If the spline data input with the SPLINE statement has one independent variable, Adams/Solver uses a
cubic polynomial to interpolate between points. If the spline data has two independent variables,
Adams/Solver first uses a cubic interpolation method to interpolate between points of the first (x)
2
y