write a simple ASCII file containing pairs of x and y values. write a simple ASCII file containing pairs of x and y values. write a file containing pairs of x and y values in Spectrum format 2, including a header. read a file containing pairs of x and y values in Spectrum format 2, including a header. ... Compute cross-correlation function for functions y1(x1) and y2(x2) The result is returned as ccfy(ccfx) Apply a velocity correction to a wavelength array. v is in units of the speed of light. ...