is too large. contains the approximate value of at the nearest valid argument. The threshold value is the same as for NE_REAL_ARG_GT in s18aec
, as defined in the Users' Note for your implementation.
5: – NagError *Input/Output
The NAG error argument (see Section 7 in the Introduction to the NAG Library CL Interface).
6Error Indicators and Warnings
Dynamic memory allocation failed.
See Section 3.1.2 in the Introduction to the NAG Library CL Interface for further information.
On entry, argument had an illegal value.
On entry, .
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.
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.
On entry, at least one value of x was invalid.
Check ivalid for more information.
Let and be the relative errors in the argument and result respectively.
If is somewhat larger than the machine precision (i.e., if is due to data errors etc.), then and are approximately related by:
Figure 1 shows the behaviour of the error amplification factor
However, if is of the same order as machine precision, then rounding errors could make slightly larger than the above relation predicts.
For small the amplification factor is approximately , which implies strong attenuation of the error, but in general can never be less than the machine precision.
For large , and we have strong amplification of errors. However, for quite moderate values of (, the threshold value), the function must fail because would overflow; hence in practice the loss of accuracy for close to is not excessive and the errors will be dominated by those of the standard function exp.
8Parallelism and Performance
Background information to multithreading can be found in the Multithreading documentation.
s18asc is not threaded in any implementation.
This example reads values of x from a file, evaluates the function at each value of and prints the results.