c/* %W%      latest revision %G% %U% */
      subroutine logplt (x,y,ye,n,ne,chart,yminx)
********************************************************************************

c *** semi-log graphing on printer,from pirk,modified by rhl
c *** x(i),y(i) are cartesian coordinates to be plotted
c *** on standard size 5cycle graph paper
c *** ne gt 0 also causes ye to be plotted on same graph
c *** ne lt o for non log polar plot
c *** ne eq -2 real and imaginary polar plot

      implicit real*8 (a-h, o-z)

      dimension x(*), y(*), chart(61,61), xf(11), ye(*)
      dimension plot(10), nplot(30)

c *** ymin must be lowest power of 10, e.g. -2.,or 3.
c *** but not smallest value of y
c ***

      data plus, pt, blank, ex      /1h+, 1h., 1h , 1hI/
      data aminus, point            /1h-, 1h+/
      data nit                      /0/

      if (nit .ne. 0) go to 20

      do 10 i=1,29
         j = i - 7
         if (i .le. 7) plot(i) = chart(i,1)
         if (i .gt. 7) nplot(j) = chart(i,1)
 10   continue

 20   nit = 1
      xmin = 0
      xmax = 180.
      ymin = yminx
      ymax = ymin + 5.

c *** polarization

      if (ne .lt. 0) ymin = -1.
      if (ne .lt. 0) ymax = 1.5
      rs = 60./(ymax - ymin)
      mm = 6

c *** construct graph

      do 30 i=1,61
         do 30 j=1,61
            chart(j,i) = blank
 30   continue

      do 40 i=1,61,10
         do 40 j=1,61,1
            chart(j,i) = pt
 40   continue

      do 50 k=1,mm
         i = (k - 1) * rs + 1.1
         if (i .gt. 61) i = 61
         do 50 j=1,61,2
            chart(i,j) = pt
 50   continue

c *** place data on graph

      xlen = (xmax - xmin)/60.
      ylen = (ymax - ymin)/60.

      do 70 i=1,n
         rhl1 = x(i)
         if (rhl1 .gt. xmax) rhl1 = xmax
         if (rhl1 .lt. xmin) rhl1 = xmin
         jx = int((rhl1 - xmin)/xlen)
         if (jx .gt. 60) jx = 60
         point = plus
         if (y(i) .le. 0.) point = aminus
         rhl = y(i)
         if (ne .lt. 0) go to 60
         y(i) = abs(y(i))
         if (y(i) .eq. 0.) y(i) = 10.**ymin
         rhl = LOG10( y(i) )
 60      continue
         if (rhl .lt. ymin) rhl = ymin
         if (rhl .gt. ymax) rhl = ymax
         iy = int((rhl - ymin)/ylen)
         if (iy .gt. 60) iy = 60
         chart(61-iy,1+jx) = point
         if ((ne .eq.-1) .or. (ne .eq. 0)) go to 70
         if (ne .eq. -2) rhl = ye(i)
         if (ne .le. 0.0)  go to 65
         if (ye(i) .le. 0.0) ye(i) = 10.**ymin
         rhl = LOG10( ye(i) )
  65     ty = 1.0
         if (rhl .lt. ymin) rhl = ymin
         if (rhl .gt. ymax) rhl = ymax
         iy = int((rhl - ymin)/ylen)
         if (iy .gt. 60) iy = 60
         point = chart(61-iy,1+jx)
         if ((point .eq. plus) .or. (point.eq.aminus)) go to 70
         chart(61-iy,1+jx) = ex
 70   continue

c *** print graph

      if (ne .ge. 0) then
         write (6,115)
         write (6,110) plot(1), (nplot(ii),ii=1,22)
      endif
      if (ne .lt. 0) then
         write(6,115)
         write (6,120) plot(1), (nplot(ii),ii=1,22)
      endif
      xlen = xlen * 100./10.
      ylen = ylen *  60./10.
      ymin = ymax
      if (ne .ge. 0) ymin = 10.**ymax

      do 90 i=1,55,6
         write (6,130) ymin, (chart(i,j),j=1,61,1)
         if (i .eq. 1) write (6,150) (plot(ii),ii=2,7)
         ymax = ymax - ylen
          ymin=ymax
         if (ne .ge. 0) ymin = 10.**ymax
         ip1 = i + 1
         ip5 = i + 5

         do 80 i1=ip1,ip5
            write (6,140) (chart(i1,j),j=1,61,1)
 80      continue
 90   continue

      write (6,130) ymin, (chart(61,j),j=1,61)

      do 100 i=1,7
         xf(i) = xmin
         xmin = xmin + xlen
 100  continue

      return

 110  format (1h+,7hsig(th),f6.1,2i4,4x,i1,i2,8i1,10i3)
 115  format (1h1)
 120  format (1h+,6h polar,f6.1,2i4,4x,i1,i2,8i1,10i3)

c *** 1h_ inserted in next line for triumf printers (1x removed after e8.2)
c *** same insertion (deletion) necessary for the Ridge.

 130  format (1h ,e8.2,101a1)
 140  format (9x,101a1)
 150  format (1h+,20x,6f7.3)
      end