On entry: these arguments are no longer referenced, but is included for backwards compatability.
7: – IntegerInput/Output
On entry: ifail must be set to , or to set behaviour on detection of an error; these values have no effect when no error is detected.
A value of causes the printing of an error message and program execution will be halted; otherwise program execution continues. A value of means that an error message is printed while a value of means that it is not.
If halting is not appropriate, the value or is recommended. If message printing is undesirable, then the value is recommended. Otherwise, the value is recommended. When the value or is used it is essential to test the value of ifail on exit.
On exit: unless the routine detects an error or a warning has been flagged (see Section 6).
6Error Indicators and Warnings
If on entry or , explanatory error messages are output on the current error message unit (as defined by x04aaf).
Errors or warnings detected by the routine:
On entry, .
On entry, .
On entry, .
An unexpected error has been triggered by this routine. Please
See Section 7 in the Introduction to the NAG Library FL 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 FL Interface for further information.
Dynamic memory allocation failed.
See Section 9 in the Introduction to the NAG Library FL Interface for further information.
In general, increasing improves the accuracy of the result until full attainable accuracy is reached, after which it might deteriorate. If lies in the central interval of the data (i.e., ), as is desirable, an upper bound on the contribution of the highest order differences (which is usually an upper bound on the error of the result) is given approximately in terms of the elements of the array g by , where , , , , for respectively, thereafter decreasing roughly by a factor of each time.
Note that if , is returned. If and , is returned. In these cases, no interpolation is necessary and there is no loss of accuracy.
8Parallelism and Performance
Background information to multithreading can be found in the Multithreading documentation.
e01abf is not threaded in any implementation.
The computation time increases as the order of increases.
This example interpolates at the point from the function values