NAG Library Function Document

nag_zamax_val (f16jsc)

1  Purpose

2  Specification

3  Description

4  References

5  Arguments

1:     n – IntegerInput

On entry: $n$, the number of elements in $x$.

Constraint: $\mathbf{n}\ge 0$.

2:     x[$\mathit{dim}$] – const ComplexInput

Note: the dimension, dim, of the array x must be at least $\max \left(1,1+\left(\mathbf{n}-1\right)\times \left|\mathbf{incx}\right|\right)$.

On entry: the vector $x$. Element $x_{\mathit{i}}$ is stored in $\mathbf{x}\left[\left(\mathit{i}-1\right)\times \left|\mathbf{incx}\right|\right]$, for $\mathit{i}=1,2,\dots ,n$.

3:     incx – IntegerInput

On entry: the increment in the subscripts of x between successive elements of $x$.

Constraint: $\mathbf{incx}\ne 0$.

4:     k – Integer *Output

On exit: $k$, the index, from the set $\left\{0,\left|\mathbf{incx}\right|,\dots ,\left(\mathbf{n}-1\right)\times \left|\mathbf{incx}\right|\right\}$, of the largest component of $x$ with respect to absolute value. If $\mathbf{n}=0$ on input then k is returned as $-1$.

5:     r – double *Output

On exit: $r$, the largest component of $x$ with respect to absolute value. If $\mathbf{n}=0$ on input then r is returned as $0.0$.

6:     fail – NagError *Input/Output

The NAG error argument (see Section 3.6 in the Essential Introduction).

6  Error Indicators and Warnings

NE_BAD_PARAM

On entry, argument $〈\mathit{\text{value}}〉$ had an illegal value.

NE_INT

On entry, $\mathbf{incx}=〈\mathit{\text{value}}〉$.
Constraint: $\mathbf{incx}\ne 0$.

On entry, $\mathbf{n}=〈\mathit{\text{value}}〉$.
Constraint: $\mathbf{n}\ge 0$.

7  Accuracy

8  Further Comments

9  Example

9.1  Program Text

Program Text (f16jsce.c)

9.2  Program Data

Program Data (f16jsce.d)

9.3  Program Results

Program Results (f16jsce.r)