The routine may be called by the names a02abf or nagf_complex_abs.
3Description
The function evaluates by using where is the larger of and , and is the smaller of and . This ensures against unnecessary overflow and loss of accuracy when calculating .
4References
Wilkinson J H and Reinsch C (1971) Handbook for Automatic Computation II, Linear Algebra Springer–Verlag
5Arguments
1: – Real (Kind=nag_wp)Input
2: – Real (Kind=nag_wp)Input
On entry: and , the real and imaginary parts of , respectively.
6Error Indicators and Warnings
None.
7Accuracy
The result should be correct to machine precision.
8Parallelism and Performance
Background information to multithreading can be found in the Multithreading documentation.