NAG CL Interface
s15asc (erf_​real_​vector)

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1 Purpose

s15asc returns an array of values of the error function erf(x)

2 Specification

#include <nag.h>
void  s15asc (Integer n, const double x[], double f[], NagError *fail)
The function may be called by the names: s15asc, nag_specfun_erf_real_vector or nag_erf_vector.

3 Description

s15asc calculates approximate values for the error function
erf(x) = 2π 0x e-t2 dt = 1-erfc(x) ,  
for an array of arguments xi, for i=1,2,,n.
See s15aec for details on the algorithm used.

4 References

None.

5 Arguments

1: n Integer Input
On entry: n, the number of points.
Constraint: n0.
2: x[n] const double Input
On entry: the argument xi of the function, for i=1,2,,n.
3: f[n] double Output
On exit: erf(xi), the function values.
4: fail NagError * Input/Output
The NAG error argument (see Section 7 in the Introduction to the NAG Library CL Interface).

6 Error Indicators and Warnings

NE_ALLOC_FAIL
Dynamic memory allocation failed.
See Section 3.1.2 in the Introduction to the NAG Library CL Interface for further information.
NE_BAD_PARAM
On entry, argument value had an illegal value.
NE_INT
On entry, n=value.
Constraint: n0.
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 7.5 in the Introduction to the NAG Library CL Interface for further information.
NE_NO_LICENCE
Your licence key may have expired or may not have been installed correctly.
See Section 8 in the Introduction to the NAG Library CL Interface for further information.

7 Accuracy

Not applicable.

8 Parallelism and Performance

s15asc is not threaded in any implementation.

9 Further Comments

None.

10 Example

This example reads values of x from a file, evaluates the function at each value of xi and prints the results.

10.1 Program Text

Program Text (s15asce.c)

10.2 Program Data

Program Data (s15asce.d)

10.3 Program Results

Program Results (s15asce.r)