NAG Library Function Document

nag_ode_bvp_ps_lin_grid_vals (d02uwc)

1  Purpose

2  Specification

3  Description

4  References

5  Arguments

1:    $\mathbf{n}$ – IntegerInput

On entry: $n$, where the number of grid points for the input data is $n+1$.

Constraint: $\mathbf{n}>0$ and n is even.

2:    $\mathbf{nip}$ – IntegerInput

On entry: the number, $m$, of grid points in the uniform mesh $\hat{x}$ onto which function values are interpolated. If $\mathbf{nip}=1$ then on successful exit from nag_ode_bvp_ps_lin_grid_vals (d02uwc), $\mathbf{fip}\left[0\right]$ will contain the value $f\left(x_n\right)$.

Constraint: $\mathbf{nip}>0$.

3:    $\mathbf{x}\left[\mathbf{n}+1\right]$ – const doubleInput

On entry: the grid points, $x_{\mathit{i}}$, for $\mathit{i}=0,1,\dots ,n$, at which the function is specified.

Usually this should be the array of Chebyshev Gauss–Lobatto points returned in nag_ode_bvp_ps_lin_cgl_grid (d02ucc).

4:    $\mathbf{f}\left[\mathbf{n}+1\right]$ – const doubleInput

On entry: the function values, $f\left(x_{\mathit{i}}\right)$, for $\mathit{i}=0,1,\dots ,n$.

5:    $\mathbf{xip}\left[\mathbf{nip}\right]$ – doubleOutput

On exit: the evenly-spaced grid points, ${\hat{x}}_{\mathit{j}}$, for $\mathit{j}=1,2,\dots ,m$.

6:    $\mathbf{fip}\left[\mathbf{nip}\right]$ – doubleOutput

On exit: the set of interpolated values $\hat{f}\left({\hat{x}}_{\mathit{j}}\right)$, for $\mathit{j}=1,2,\dots ,m$. Here $\hat{f}\left({\hat{x}}_{\mathit{j}}\right)\approx f\left(x={\hat{x}}_{\mathit{j}}\right)$.

7:    $\mathbf{fail}$ – NagError *Input/Output

The NAG error argument (see Section 3.6 in the Essential Introduction).

6  Error Indicators and Warnings

NE_ALLOC_FAIL

Dynamic memory allocation failed.
See Section 3.2.1.2 in the Essential Introduction for further information.

NE_BAD_PARAM

On entry, argument $〈\mathit{\text{value}}〉$ had an illegal value.

NE_INT

On entry, $\mathbf{n}=〈\mathit{\text{value}}〉$.
Constraint: $\mathbf{n}>0$.

On entry, $\mathbf{n}=〈\mathit{\text{value}}〉$.
Constraint: n is even.

On entry, $\mathbf{nip}=〈\mathit{\text{value}}〉$.
Constraint: $\mathbf{nip}>0$.

NE_INTERNAL_ERROR

An internal error has occurred in this function. Check the function call and any array sizes. If the call is correct then please contact NAG for assistance.

An unexpected error has been triggered by this function. Please contact NAG.
See Section 3.6.6 in the Essential Introduction for further information.

NE_NO_LICENCE

Your licence key may have expired or may not have been installed correctly.
See Section 3.6.5 in the Essential Introduction for further information.

7  Accuracy

8  Parallelism and Performance

9  Further Comments

10  Example

10.1  Program Text

Program Text (d02uwce.c)

10.2  Program Data

Program Data (d02uwce.d)

10.3  Program Results

Program Results (d02uwce.r)