docs: function mgf( y, x, n, p, clbk ) {
  	var len = x.length,
  		fcn,
  		v, i;
  
  	fcn = partial( n, p );
  	for ( i = 0; i < len; i++ ) {
  		v = clbk( x[ i ], i );
  		if ( typeof v === 'number' ) {
  			y[ i ] = fcn( v );
  		} else {
  			y[ i ] = NaN;
  		}
  	}
  	return y;
  }