function logspace( a, b, len ) {
	var arr;
	var N;
	var d;
	var i;

	if ( len === 0 ) {
		return [];
	}
	// Calculate the increment:
	N = len - 1;
	d = ( b-a ) / N;

	// Build the output array...
	arr = [ pow( 10, a ) ];
	for ( i = 1; i < N; i++ ) {
		arr.push( pow( 10, a+(d*i) ) );
	}
	arr.push( pow( 10, b ) );
	return arr;
}
Generates a logarithmically spaced numeric array.

@param {number} a - exponent of start value
@param {number} b - exponent of end value
@param {NonNegativeInteger} len - length of output array
@returns {Array} logarithmically spaced numeric array

@example
var arr = logspace( 0, 2, 6 );
// returns [ 1, ~2.5, ~6.31, ~15.85, ~39.81, 100 ]