NAG C Library Function Document

nag_bessel_k1_scaled_vector (s18crc)

1

Purpose

2

Specification

3

Description

4

References

5

Arguments

1:    $\mathbf{n}$ – IntegerInput

On entry: $n$, the number of points.

Constraint: $\mathbf{n}\ge 0$.

2:    $\mathbf{x}\left[\mathbf{n}\right]$ – const doubleInput

On entry: the argument $x_{\mathit{i}}$ of the function, for $\mathit{i}=1,2,\dots ,\mathbf{n}$.

Constraint: $\mathbf{x}\left[\mathit{i}-1\right]>0.0$, for $\mathit{i}=1,2,\dots ,\mathbf{n}$.

3:    $\mathbf{f}\left[\mathbf{n}\right]$ – doubleOutput

On exit: $e^{x_i}{K}_1\left(x_i\right)$, the function values.

4:    $\mathbf{ivalid}\left[\mathbf{n}\right]$ – IntegerOutput

On exit: $\mathbf{ivalid}\left[\mathit{i}-1\right]$ contains the error code for $x_{\mathit{i}}$, for $\mathit{i}=1,2,\dots ,\mathbf{n}$.

$\mathbf{ivalid}\left[i-1\right]=0$

No error.

$\mathbf{ivalid}\left[i-1\right]=1$

On entry,

$x_i\le 0.0$, $K_1\left(x_i\right)$ is undefined. $\mathbf{f}\left[\mathit{i}-1\right]$ contains $0.0$.

$\mathbf{ivalid}\left[i-1\right]=2$

$x_i$ is too close to zero, as determined by the value of the safe-range parameter nag_real_safe_small_number (X02AMC): there is a danger of causing overflow. $\mathbf{f}\left[\mathit{i}-1\right]$ contains the reciprocal of the safe-range parameter.

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

The NAG error argument (see Section 3.7 in How to Use the NAG Library and its Documentation).

6

Error Indicators and Warnings

NE_ALLOC_FAIL

Dynamic memory allocation failed.
See Section 2.3.1.2 in How to Use the NAG Library and its Documentation 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: $\mathbf{n}\ge 0$.

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.
See Section 2.7.6 in How to Use the NAG Library and its Documentation for further information.

NE_NO_LICENCE

Your licence key may have expired or may not have been installed correctly.
See Section 2.7.5 in How to Use the NAG Library and its Documentation for further information.

NW_IVALID

On entry, at least one value of x was invalid.
Check ivalid for more information.

7

Accuracy

8

Parallelism and Performance

9

Further Comments

10

Example

10.1

Program Text

Program Text (s18crce.c)

10.2

Program Data

Program Data (s18crce.d)

10.3

Program Results

Program Results (s18crce.r)