SUBROUTINE PHIST

 PHIST is a generalized  histogram plotting program with various plot format controls. Shading may done under the histogram columns. The histogram height may be plotted on top of each histogram column vertically. The mean and +/- sigma variations may be indicated on the plot output. Note: PHIST does not do the histogramming. This is left to the user.

CALL PHIST(a,n,t,nt,xl,yl,s,ns,xt,nxt,xm,xx,ax,
             iflag,ishad,am,as<,ic>)

a     (R): array of heights of histogram columns
n     (I): number of points in a array to plot
t     (C): title string
nt    (I): number of characters in t
           = 0 : no title
           < 0 : use color array
xl    (R): length of x axis in inches (integer-valued real number)
yl    (R): length of y axis in inches (integer-valued real number)
s     (C): subtitle string
ns    (I): number of characters in s
xt    (C): x axis title
nxt   (I): number of characters in xt
xm    (R): minimum value displayed on x axis
xx    (R): maximum value displayed on x axis
ax    (R): maximum value of a
iflag (I): option flag
           < 0 : do not close LONGLIB after plotting
           = 0 : close LONGLIB--no plot produced
           > 0 : close LONGLIB after plotting
(magnitude) > 10000 : do not initialize LONGLIB before plotting
(1's digit)  = 2 : plot number value of column on top of column
             = 1 : no numeric values on top of histogram columns
             = 0 : no axis or title (histogram columns only)
(10's digit) = 0 : Ask which screen device to use
            <> 0 : Screen Device Number (see FRAME)
ishad (I): shade option flag
           < 0 : shade with solid line
           = 0 : no shading
           > 0 : shade with line of type ishad
am    (R): mean value of histogram to plot (in relation to xm,xx)
as    (R): standard deviation of histogram to plot
           < 0 : neither mean nor sigma values indicated on plot
           = 0 : only mean value indicated on plot
           > 0 : mean and +/- sigma values indicated on plot
ic    (I): color list
           ic(1) : color for axis lines
           ic(2) : color for axis numbers
           ic(3) : color for axis titles
           ic(4) : color for axis exponents
           ic(5) : color for mean label
           ic(6) : color for sigma label
           ic(7) : color for title
           ic(8) : color for subtitle
           ic(9) : color for histogram columns (return)

common /cphist/xmr,dxr,ymr,dyr

xmr   (R): returned value of xmin
dxr   (R): returned value of scale factor (xmax-xmin)/xlen
ymr   (R): returned value of ymin
dyr   (R): returned value of scale factor (ymax-ymin)/ylen