function createBenchmark( N ) {
	var AP = uniform( N * ( N + 1 ) / 2, -10.0, 10.0, options );
	var x = uniform( N, -10.0, 10.0, options );
	return benchmark;

	/**
	* Benchmark function.
	*
	* @private
	* @param {Benchmark} b - benchmark instance
	*/
	function benchmark( b ) {
		var z;
		var i;

		b.tic();
		for ( i = 0; i < b.iterations; i++ ) {
			z = dspr( 'row-major', 'upper', N, 1.0, x, 1, AP );
			if ( isnan( z[ i%z.length ] ) ) {
				b.fail( 'should not return NaN' );
			}
		}
		b.toc();
		if ( isnan( z[ i%z.length ] ) ) {
			b.fail( 'should not return NaN' );
		}
		b.pass( 'benchmark finished' );
		b.end();
	}
}
Creates a benchmark function.

@private
@param {PositiveInteger} N - number of elements along each dimension
@returns {Function} benchmark function