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.
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, .
The function has been called with an argument less than , for which is not defined.
If and are the relative errors in the argument and result respectively, then in principle
That is the relative error in the argument is amplified by a factor at least in the result. The equality should apply if is greater than the machine precision ( due to data errors etc.) but if is simply a result of round-off in the machine representation it is possible that an extra figure may be lost in internal calculation and round-off. The behaviour of the amplification factor is shown in the following graph:
It should be noted that for the factor is always less than . For large we have the absolute error in the result, in principle, given by
This means that eventually accuracy is limited by machine precision. More significantly for close to , , the above analysis becomes inapplicable due to the fact that both function and argument are bounded, , . In this region we have
That is, there will be approximately half as many decimal places correct in the result as there were correct figures in the argument.
8Parallelism and Performance
s11acc is not threaded in any implementation.
This example reads values of the argument from a file, evaluates the function at each value of and prints the results.