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The documentation for the current release is also available on this site.
NAG Library Manual, Mark 27.3
Interfaces:  FL   CL   CPP   AD 
NAG FL Interface Introduction
F06 (Blas) Chapter Contents
F06 (Blas) Chapter Introduction
f06jm:  FL   CL   CPP   AD 

NAG FL Interface
f06jmf (izamax)

NAG Library Manual, Mark 27.3
Interfaces:  FL   CL   CPP   AD 
NAG FL Interface Introduction
F06 (Blas) Chapter Contents
F06 (Blas) Chapter Introduction
f06jm:  FL   CL   CPP   AD 

▸▿ Contents

© The Numerical Algorithms Group Ltd. 2021
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1 Purpose

f06jmf computes the index of the absolutely largest component of a complex vector.

2 Specification

Fortran Interface
Function f06jmf ( n, x, incx)
Integer :: f06jmf
Integer, Intent (In) :: n, incx
Complex (Kind=nag_wp), Intent (In) :: x(*)
C Header Interface
#include <nag.h>
Integer  f06jmf_ (const Integer *n, const Complex x[], const Integer *incx)
The routine may be called by the names f06jmf, nagf_blas_izamax or its BLAS name izamax.

3 Description

f06jmf returns, via the function name, the smallest index i such that
|Re(xi)|+|Im(xi)|=maxj(|Re(xj)|+|Im(xj)|)  
where x is an n-element complex vector scattered with stride incx.

4 References

Lawson C L, Hanson R J, Kincaid D R and Krogh F T (1979) Basic linear algebra supbrograms for Fortran usage ACM Trans. Math. Software 5 308–325

5 Arguments

1: n – Integer Input
On entry: n, the number of elements in x.
2: x(*) – Complex (Kind=nag_wp) array Input
Note: the dimension of the array x must be at least max(1, 1+(n-1) ×incx ) .
On entry: the n-element vector x. xi must be stored in x(1+(i-1)×incx), for i=1,2,…,n.
Intermediate elements of x are not referenced.
3: incx – Integer Input
On entry: the increment in the subscripts of x between successive elements of x.
Constraint: incx>0.

6 Error Indicators and Warnings

None.

7 Accuracy

Not applicable.

8 Parallelism and Performance

f06jmf is not threaded in any implementation.

9 Further Comments

None.

10 Example

None.
NAG Library Manual, Mark 27.3
Interfaces:  FL   CL   CPP   AD 
NAG FL Interface Introduction
F06 (Blas) Chapter Contents
F06 (Blas) Chapter Introduction
f06jm:  FL   CL   CPP   AD 
© The Numerical Algorithms Group Ltd. 2021