F06BCF (PDF version)
F06 Chapter Contents
F06 Chapter Introduction
NAG Library Manual
NAG Library Routine Document
F06BCF
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
Parameters
6
Error Indicators and Warnings
7
Accuracy
8
Parallelism and Performance
9
Further Comments
10
Example
1 Purpose
F06BCF reconstructs the parameters
c
and
s
of a real plane rotation from the tangent of that rotation.
2 Specification
SUBROUTINE F06BCF (
T
,
C
,
S
)
REAL (KIND=nag_wp)
T, C, S
3 Description
F06BCF reconstructs the parameters
c
and
s
of a real plane rotation from the value of the tangent
t
, as returned by
F06BAF
:
c
=
1
1
+
t
2
,
s
=
c
t
,
so that
c
≥
0
and
s
has the same sign as
t
.
If
t
<
ε
, where
ε
is the
machine precision
, the routine sets
c
=
1
and
s
=
t
; if
t
>
1
/
ε
, the routine sets
c
=
1
t
and
s
=
sign
t
.
4 References
None.
5 Parameters
1:
T
– REAL (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
– REAL (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
Not applicable.
9 Further Comments
None.
10 Example
None.
F06BCF (PDF version)
F06 Chapter Contents
F06 Chapter Introduction
NAG Library Manual
© The Numerical Algorithms Group Ltd, Oxford, UK. 2015