Please see examples for the format of the input file
lr_input
	prefix		’pwscf’
		Prefix of the files generated by the previous turbo_lanczos.x 
		run.
	outdir		’./’
		The directory where the output files produced by the previous
		 turbo_lanczos.x run are stored.
	itermax0	500
		Number of Lanczos coefficients to be read from the file.
	itermax		500
		The total number of Lanczos coefficients that will be considered
		 in the calculation of the polarizability/absorption 
		coefficient. If itermax >itermax0, the Lanczos coefficients 
		in between itermax0+1 and itermax will be extrapolated.
	terminator	’no’
		Sets the extrapolation scheme. ’osc’= biconstant extrapolation;
		 ’constant’=constant extrapolation; ’no’=no extrapolation.
	epsil		0.02
		The broadening/damping term (in Rydberg units).
	units		0
		Unit system used. 0: Rydbergs; 1: Electron volts 
		2: Nanometers/Electron volts
	start		0.0
		The polarizability and the absorption coefficient are computed 
		starting from this value. In units set by the units variable.
	end		2.5
		The polarizability and the absorption coefficient are computed
		 up to this value. In units set by the units variable.
	increment	0.001
		Incremental step used to define the mesh between start and end.
		 In units set by the units variable.
	ipol		1
		An integer variable that determines which element of the 
		dynamical polarizability will be computed: 
		1 → αxx(ω), 2 → αyy(ω), and 3 → αzz(ω). When set to 4 
		the polarizability tensor and oscillator strength function 
		are computed.
	verbosity	0
		This integer variable Controls the output verbosity.
