Basic Linear Algebra Subprograms Technical (BLAST) Forum (2001) Basic Linear Algebra Subprograms Technical (BLAST) Forum Standard University of Tennessee, Knoxville, Tennessee http://www.netlib.org/blas/blast-forum/blas-report.pdf

Parameters

Compulsory Input Parameters

1: $n$ – int64int32nag_int scalar: $n$ , the number of elements in $x$ .
2: $x (1 + (n - 1) \times |incx|)$ – double array: The vector $x$ . Element $x_{i}$ is stored in $x ((i - 1) \times |incx| + 1)$ , for $i = 1, 2, \dots, n$ .
3: $incx$ – int64int32nag_int scalar: The increment in the subscripts of x between successive elements of $x$ .

Constraint: $incx \neq 0$ .

Optional Input Parameters

None.

Output Parameters

1: $result$ – double scalar: The result of the function.

Error Indicators and Warnings

incx = 0

, an error message is printed and program execution is terminated.

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)).

Further Comments

None.

Example

This example computes the sum of the elements of

x = {(1.1, 10.2, 11.5, - 2.7, 9.2)}^{T} .

Open in the MATLAB editor: f16el_example

function f16el_example


fprintf('f16el example results\n\n');

% sum x
n    = int64(5);
x    = [1.1   10.2    11.5   -2.7    9.2];
incx = int64(1);

[xsum] = f16el(n, x, incx);

fprintf('sum(');
fprintf('%7.1f',x);
fprintf(') = %7.1f\n',xsum);

f16el example results

sum(    1.1   10.2   11.5   -2.7    9.2) =    29.3

PDF version (NAG web site, 64-bit version, 64-bit version)

Chapter Contents

Chapter Introduction

NAG Toolbox