F06CCF (PDF version)
F06 Chapter Contents
F06 Chapter Introduction
NAG Library Manual

NAG Library Routine Document

F06CCF

Note:  before using this routine, please read the Users' Note for your implementation to check the interpretation of bold italicised terms and other implementation-dependent details.

▸▿ Contents

    1  Purpose
    2  Specification
    3  Description
    4  References
    5  Arguments
    6  Error Indicators and Warnings
    7  Accuracy
    8  Parallelism and Performance
    9  Further Comments
    10  Example

1  Purpose

F06CCF reconstructs the parameters c (real) and s (complex) of a complex plane rotation from the tangent of that rotation.

2  Specification

SUBROUTINE F06CCF ( T, C, S)
REAL (KIND=nag_wp)  C
COMPLEX (KIND=nag_wp)  T, S

3  Description

F06CCF reconstructs the parameters c (real) and s (complex) of a complex plane rotation, from the value of the tangent t, as returned by F06CAF:
c=11+t2 ,  s=ct,  
so that c is always real and non-negative.
If t<ε, where ε is the machine precision, the routine sets c=1 and s=t.

4  References

None.

5  Arguments

1:     T – COMPLEX (KIND=nag_wp)Input
On entry: the value t, the tangent of the rotation.
2:     C – REAL (KIND=nag_wp)Output
On exit: the value c, the cosine of the rotation.
3:     S – COMPLEX (KIND=nag_wp)Output
On exit: the value s, the sine of the rotation.

6  Error Indicators and Warnings

None.

7  Accuracy

Not applicable.

8  Parallelism and Performance

F06CCF is not threaded in any implementation.

9  Further Comments

None.

10  Example

None.
F06CCF (PDF version)
F06 Chapter Contents
F06 Chapter Introduction
NAG Library Manual
© The Numerical Algorithms Group Ltd, Oxford, UK. 2016