;+
; NAME:
;  mk_nuwgt_low
; PURPOSE: (one line)
;  make a list of inverse cm (and optionally, weights) (lowlevel)
; DESCRIPTION:
;  pick nu's appropriate for the temperature
; CATEGORY:
;  Spectra
; CALLING SEQUENCE:
;  nuarr = mk_nuwgt_low(nu0arr, dopwarr, nx, ndopw, s, ng, dnuarr)
; INPUTS:
;  nu0arr - array of line centers (may be scalar)
;  dopwarr - array of doppler widths (same length as nu0arr)
;  nx - number of points in all other grids
;  ndopw - number of doppler widths in the core
;  s - scale of spacing between grids (must be >1 )
;  ng - number of grids
; OPTIONAL INPUT PARAMETERS:
;  none
; KEYWORD INPUT PARAMETERS:
;  none
; KEYWORD OUTPUT PARAMETERS:
;  none
; OUTPUTS:
;  nu - array of wavenumbers (inverse cm)
;  dnuarr - if present, array of wavenumber weights (inverse cm)
; COMMON BLOCKS:
;  None
; SIDE EFFECTS:
; RESTRICTIONS:
;  None
; PROCEDURE:
; MODIFICATION HISTORY:
;  Written 2001 May, by Leslie Young, SwRI
;  Modified 2004 Jun 27, LAY, based on Meadows&Crisp 1996
;-

function drop1, a
    return, a[1:n_elements(a)-1]
end

function drop1rev, a
    return, reverse(a[1:n_elements(a)-1])
end

; muwgt1234   xmin <= xl  and xu <= xmax
function muwgt1234, xl, xu, nx, d
    x = xl + (findgen(nx)+0.5)*d
    return, x
end

; muwgt1243   xmin <= xl  and xmax < xu
function muwgt1243, xl, max, nx, d
    n = floor( (xmax-xl)/d + 0.5)
    if n le 0 then begin
        x = [xmax]
    endif else begin
        x = xl + (findgen(n)+0.5)*d
        if x[n-1] lt xmax then begin
            x = [x, xmax]
        end
    endelse
    return, x
end

; muwgt2134   xl < xmin and xu <= xmax
function muwgt2134, xmin, xu, nx, d
    n = floor( (xu-xmin)/d + 0.5)
    if n le 0 then begin
        x = [xmin]
    endif else begin
        x = xu - (n - 0.5 - findgen(n))*d
        if x[0] gt xmin then begin
            x = [xmin, x]
        end
    endelse
    return, x
    
end

; muwgt2143   xl < xmin and xmax < xu
function muwgt2134, xl, xmin,xmax,  xu, nx, d
    i0 = ceil( (xmin-xl)/d + 0.5)
    n = floor( (max-xl)/d + 0.5)
    if n le 0 then begin
        if xmin eq xmax then begin
            x = [xmin]
        endif else begin
            x = [xmin, xmax]
        endelse
    endif else begin
        x = xl + (findgen(n) + i0 + 0.5)*d
        if x[n-1] lt xmax then begin
            x = [x, xmax]
        end
        if x[0] gt xmin then begin
            x = [xmin, x]
        end
    endelse
    return, x
    
end



; shortward of the first line, 
; numin < nu0b
function mk_nuwgt_low1, nu0b, dopwb, nx, ndopw, s, numin

    db = 2*(ndopw*dopwb)/nx
    nub = nu0b-db/2.
    xb = nu0b + [0.]
    nubnext = nub - db * nx 
    while nubnext ge numin do begin
        xb = [xb, nub - (findgen(nx)+0.5)*db]
        nub = nubnext
        db = db * s
        nubnext = nub - db * nx 
    endwhile
    nb = floor((nub-numin)/db+0.5)
    if nb gt 0 then begin
        xb = [xb, nub - (findgen(nb)+0.5)*db]
    endif 
    if (nub - (nb-0.5)*db) gt numin then $
      xb = [xb, numin]
    nuarr = drop1rev(xb)
    return, nuarr
end

pro mk_nuwgt_low1TEST
    nu0b=0.
    dopwb=1.
    nx = 10.
    ndopw = 1.
    s = 2.
    
    numin = -0.1
    print, 'numin=',numin
    print, mk_nuwgt_low1(nu0b, dopwb, nx, ndopw, s, numin)
    
    numin = -0.2
    print, 'numin=',numin
    print, mk_nuwgt_low1(nu0b, dopwb, nx, ndopw, s, numin)
    
    numin = -0.3
    print, 'numin=',numin
    print, mk_nuwgt_low1(nu0b, dopwb, nx, ndopw, s, numin)
    
    numin = -0.7
    print, 'numin=',numin
    print, mk_nuwgt_low1(nu0b, dopwb, nx, ndopw, s, numin)
    
    numin = -0.8
    print, 'numin=',numin
    print, mk_nuwgt_low1(nu0b, dopwb, nx, ndopw, s, numin)
    
    numin = -0.9
    print, 'numin=',numin
    print, mk_nuwgt_low1(nu0b, dopwb, nx, ndopw, s, numin)
    
    numin = -2.1
    print, 'numin=',numin
    print, mk_nuwgt_low1(nu0b, dopwb, nx, ndopw, s, numin)
    
    numin = -2.3
    print, 'numin=',numin
    print, mk_nuwgt_low1(nu0b, dopwb, nx, ndopw, s, numin)
    
    numin = -4.
    print, 'numin=',numin
    print, mk_nuwgt_low1(nu0b, dopwb, nx, ndopw, s, numin)
end