NAG FL Interface
f16jpf (dmin_​val)

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FL Specification Language:

1 Purpose

f16jpf computes the smallest component of a real vector, along with the index of that component.

2 Specification

Fortran Interface
Subroutine f16jpf ( n, x, incx, k, r)
Integer, Intent (In) :: n, incx
Integer, Intent (Out) :: k
Real (Kind=nag_wp), Intent (In) :: x(1+(n-1)*ABS(incx))
Real (Kind=nag_wp), Intent (Out) :: r
C Header Interface
#include <nag.h>
void  f16jpf_ (const Integer *n, const double x[], const Integer *incx, Integer *k, double *r)
The routine may be called by the names f16jpf, nagf_blast_dmin_val or its BLAST name blas_dmin_val.

3 Description

f16jpf computes the smallest component, r, of an n-element real vector x, and determines the smallest index, k, such that

4 References

Basic Linear Algebra Subprograms Technical (BLAST) Forum (2001) Basic Linear Algebra Subprograms Technical (BLAST) Forum Standard University of Tennessee, Knoxville, Tennessee

5 Arguments

1: n Integer Input
On entry: n, the number of elements in x.
2: x(1+(n-1)×|incx|) Real (Kind=nag_wp) array Input
On entry: the n-element vector x.
If incx>0, xi must be stored in x((i-1)×incx+1), for i=1,2,,n.
If incx<0, xi must be stored in x((n-i)×|incx|+1), for i=1,2,,n.
Intermediate elements of x are not referenced. If n=0, x is not referenced.
3: incx Integer Input
On entry: the increment in the subscripts of x between successive elements of x.
Constraint: incx0.
4: k Integer Output
On exit: k, the index, from the set {1,2,,n} , of the smallest component of x. If n0 on input then k is returned as 0.
5: r Real (Kind=nag_wp) Output
On exit: r, the smallest component of x. If n0 on input then r is returned as 0.0.

6 Error Indicators and Warnings

If incx=0, an error message is printed and program execution is terminated.

7 Accuracy

The BLAS standard requires accurate implementations which avoid unnecessary over/underflow (see Section 2.7 of Basic Linear Algebra Subprograms Technical (BLAST) Forum (2001)).

8 Parallelism and Performance

f16jpf is not threaded in any implementation.

9 Further Comments


10 Example

This example computes the smallest component and index of that component for the vector
x= (1,10,11,-2,9) T .  

10.1 Program Text

Program Text (f16jpfe.f90)

10.2 Program Data

Program Data (f16jpfe.d)

10.3 Program Results

Program Results (f16jpfe.r)