[Plplot-cvs] plplot/examples/f77 x22f.fm4,1.2,1.3

[Andrew R. <and...@us...>]

Update of /cvsroot/plplot/plplot/examples/f77
In directory sc8-pr-cvs1.sourceforge.net:/tmp/cvs-serv7265/examples/f77

Modified Files:
	x22f.fm4 
Log Message:

Add plvect and plsvect to the common API.

Add java, python and tcl bindings and examples for plvect and plsvect. 

Modify example 22 and make C, C++, fortran, java, python and tcl versions 
consistent. C, C++, fortran and tcl versions of example 22 now produce 
identical results. There appear to be some rounding errors with java and
python.


Index: x22f.fm4
===================================================================
RCS file: /cvsroot/plplot/plplot/examples/f77/x22f.fm4,v
retrieving revision 1.2
retrieving revision 1.3
diff -u -d -r1.2 -r1.3
--- x22f.fm4	24 Feb 2004 10:06:08 -0000	1.2
+++ x22f.fm4	21 May 2004 15:09:26 -0000	1.3
@@ -2,6 +2,7 @@
 C      Vector plot demo.
 C
 C      Copyright (C) 2004  Alan W. Irwin
+C      Copyright (C) 2004  Andrew Ross
 C
 C      This file is part of PLplot.
 C
@@ -21,15 +22,6 @@
 
 C      Does several contour plots using different coordinate mappings.
       implicit none
-      real*8 PI
-      parameter (PI = 3.1415926535897932384d0)
-      integer i, j, nx, ny, npts
-      parameter (nx=10, ny=10)
-
-      real*8 u(nx, ny), v(nx, ny), xg(nx,ny), yg(nx,ny)
-
-      real*8 dx, dy, dr, xmin, xmax, ymin, ymax
-      real*8 xx, yy, r, theta, scaling
 
       integer narr, fill
       parameter (narr=6)
@@ -46,95 +38,231 @@
 C      Process command-line arguments
       call plparseopts(PL_PARSE_FULL)
 
+      call plinit
+
+
+      call circulation
+
+      fill = 0
+
+C     Set arrow style using arrow_x and arrow_y the
+C     plot using these arrows
+      call plsvect(arrow_x, arrow_y, narr, fill)
+      call constriction
+
+C     Set arrow style using arrow_x and arrow_y the
+C     plot using these arrows
+      fill = 1
+      call plsvect(arrow2_x, arrow2_y, narr, fill)
+      call constriction
+
+      call potential
+
+      call plend
+      
+      end
+
+C     vector plot of the circulation around the origin
+      subroutine circulation()
+      implicit none
+
+      integer i, j, nx, ny
+      parameter (nx=20, ny=20)
+
+      real*8 u(nx, ny), v(nx, ny), xg(nx,ny), yg(nx,ny)
+
+      real*8 dx, dy, xmin, xmax, ymin, ymax
+      real*8 xx, yy, scaling
+
       dx = 1.0d0
       dy = 1.0d0
 
-      npts = nx*ny
-      xmin = -nx/2.0d0*dx
-      xmax = nx/2.0d0*dx
-      ymin = -ny/2.0d0*dy
-      ymax = ny/2.0d0*dy
+      xmin = -dble(nx)/2.0d0*dx
+      xmax = dble(nx)/2.0d0*dx
+      ymin = -dble(ny)/2.0d0*dy
+      ymax = dble(ny)/2.0d0*dy
 
-C      Calculate the data matrices.
       do i=1,nx
-        xx = dble(i-1-0.5*nx+0.5)*dx
+        xx = (dble(i)-nx/2.0d0-0.5d0)*dx
         do j=1,ny
-          yy = dble(j-1-0.5*ny+0.5)*dy
+          yy = (dble(j)-ny/2.0d0-0.5d0)*dy
 	  xg(i,j) = xx
 	  yg(i,j) = yy
           u(i,j) = yy
           v(i,j) = -xx
         enddo
       enddo
-      print*,xg(nx/2,ny/2),yg(nx/2,ny/2)
-
-      call plinit
 
-C      Plot vectors using default arrow style
       call plenv(xmin, xmax, ymin, ymax, 0, 0)
       call pllab('(x)', '(y)', 
-     &	'#frPLplot Example 22 - vector plot')
+     &	'#frPLplot Example 22 - circulation')
       call plcol0(2)
-C      Plot using auto scaling
       scaling = 0.0d0
       call plvec2(u,v,nx,ny,scaling,xg,yg)
       call plcol0(1)
 
-      fill = 0
+      end
 
-C      Create user defined arrow style and plot vectors using new style
-      call plsvect(arrow_x, arrow_y, narr, fill)
-      call plenv(xmin, xmax, ymin, ymax, 0, 0)
-      call pllab('(x)', '(y)', 
-     &	'#frPLplot Example 22 - user defined arrow')
-      call plcol0(2)
-C      Plot using 0.5 * auto scaling
-      scaling = -0.5
-      call plvec2(u,v,nx,ny,scaling,xg,yg)
-      call plcol0(1)
+C     vector plot of the flow through a constricted pipe
+      subroutine constriction()
+      implicit none
 
-      fill = 1
+      real*8 PI
+      parameter (PI = 3.1415926535897932384d0)
+
+      integer i, j, nx, ny
+      parameter (nx=20, ny=20)
+
+      real*8 u(nx, ny), v(nx, ny), xg(nx,ny), yg(nx,ny)
+
+      real*8 dx, dy, xmin, xmax, ymin, ymax
+      real*8 xx, yy, Q, b, dbdx, scaling
+
+      dx = 1.0d0
+      dy = 1.0d0
+
+      xmin = -dble(nx)/2.0d0*dx
+      xmax = dble(nx)/2.0d0*dx
+      ymin = -dble(ny)/2.0d0*dy
+      ymax = dble(ny)/2.0d0*dy
+
+      Q = 2.0d0
+      do i=1,nx
+        xx = (dble(i)-dble(nx)/2.0d0-0.5d0)*dx
+        do j=1,ny
+          yy = (dble(j)-dble(ny)/2.0d0-0.5d0)*dy
+	  xg(i,j) = xx
+	  yg(i,j) = yy
+          b = ymax/4.0d0*(3.0d0-cos(PI*xx/xmax))
+          if (abs(yy).lt.b) then
+             dbdx = ymax/4.0d0*sin(PI*xx/xmax)*yy/b
+             u(i,j) = Q*ymax/b
+             v(i,j) = u(i,j)*dbdx
+          else
+             u(i,j) = 0.0d0
+             v(i,j) = 0.0d0
+          endif
+        enddo
+      enddo
 
-C      Create user defined arrow style and plot vectors using new style
-      call plsvect(arrow2_x, arrow2_y, narr, fill)
       call plenv(xmin, xmax, ymin, ymax, 0, 0)
       call pllab('(x)', '(y)', 
-     &	'#frPLplot Example 22 - filled arrow')
+     &	'#frPLplot Example 22 - constriction')
       call plcol0(2)
-C      Plot using user supplied scaling
-      scaling = 0.3
+      scaling = -0.5d0
       call plvec2(u,v,nx,ny,scaling,xg,yg)
       call plcol0(1)
 
-C      Example of a polar plot
+      end
 
-C      Calculate the data matrices.
-      dr = 0.5
 
-      do i=1,nx
-        r = dble((i-1)*dr)
-        do j=1,ny
-          theta = dble(2.0d0*PI/dble(ny-1)*dble(j-1))
-	  xg(i,j) = r*cos(theta)
-	  yg(i,j) = r*sin(theta)
-          u(i,j) = yg(i,j)
-          v(i,j) = -xg(i,j)
+      subroutine potential()
+      implicit none
+
+      real*8 PI
+      parameter (PI = 3.1415926535897932384d0)
+
+      integer i, j, nr, ntheta, nper, nlevel
+      parameter (nr=20, ntheta=20, nper=100, nlevel=10)
+
+      real*8 u(nr, ntheta), v(nr, ntheta), z(nr, ntheta)
+      real*8 xg(nr,ntheta), yg(nr,ntheta)
+      real*8 clevel(nlevel), px(nper), py(nper)
+
+      real*8 xmin, xmax, ymin, ymax, zmin, zmax, rmax
+      real*8 xx, yy, r, theta, scaling, dz
+
+      real*8 eps, q1, d1, q1i, d1i, q2, d2, q2i, d2i
+      real*8 div1, div1i, div2, div2i
+
+      rmax = dble(nr)
+
+      eps = 2.0d0
+
+      q1 = 1.0d0;
+      d1 = rmax/4.0d0;
+      
+      q1i = - q1*rmax/d1;
+      d1i = rmax**2.0d0/d1;
+      
+      q2 = -1.0d0;
+      d2 = rmax/4.0d0;
+      
+      q2i = - q2*rmax/d2;
+      d2i = rmax**2.0d0/d2;
+           
+      do i = 1, nr
+         r = 0.5 + dble(i-1)
+        do j = 1, ntheta
+          theta = 2.*PI/dble(ntheta-1)*(dble(j)-0.5)
+          xx = r*cos(theta)
+          yy = r*sin(theta) 
+          xg(i,j) = xx
+          yg(i,j) = yy
+          div1 = sqrt((xg(i,j)-d1)**2 + (yg(i,j)-d1)**2 + eps**2)
+          div1i = sqrt((xg(i,j)-d1i)**2 + (yg(i,j)-d1i)**2 + eps**2)
+
+          div2 = sqrt((xg(i,j)-d2)**2 + (yg(i,j)+d2)**2 + eps**2)
+          div2i = sqrt((xg(i,j)-d2i)**2 + (yg(i,j)+d2i)**2 + eps**2)
+
+          z(i,j) = q1/div1 + q1i/div1i + q2/div2 + q2i/div2i
+          u(i,j) = -q1*(xx-d1)/div1**3 - q1i*(xx-d1i)/div1i**3 -
+     1         q2*(xx-d2)/div2**3 - q2i*(xx-d2i)/div2i**3
+          v(i,j) = -q1*(yy-d1)/div1**3 - q1i*(yy-d1i)/div1i**3 -
+     1         q2*(yy+d2)/div2**3 - q2i*(yy+d2i)/div2i**3
         enddo
       enddo
 
-      xmin = -nx*dr
-      xmax = nx*dr
-      ymin = -ny*dr
-      ymax = ny*dr
+      call a2mnmx(xg, nr, ntheta, xmin, xmax, nr)
+      call a2mnmx(yg, nr, ntheta, ymin, ymax, nr)
+      call a2mnmx(z, nr, ntheta, zmin, zmax, nr)
 
       call plenv(xmin, xmax, ymin, ymax, 0, 0)
       call pllab('(x)', '(y)', 
-     &	'#frPLplot Example 22 - polar vector plot')
+     &	'#frPLplot Example 22 - potential gradient vector plot')
+
+C     plot contours of the potential
+      dz = abs(zmax - zmin)/dble (nlevel)
+      do i = 1, nlevel
+         clevel(i) = zmin + (i-0.5d0)*dz
+      enddo
+      call plcol0(3)
+      call pllsty(2)
+      call plcon2(z,nr,ntheta,1,nr,1,ntheta,clevel,nlevel,xg,yg)
+      call pllsty(1)
+      call plcol0(1)
+
       call plcol0(2)
-      scaling = 0.5
-      call plvec2(u,v,nx,ny,scaling,xg,yg)
+      scaling = 25.0d0
+      call plvec2(u,v,nr,ntheta,scaling,xg,yg)
       call plcol0(1)
 
-      call plend
-      
+      do i=1,nper
+         theta = 2.0d0*PI/dble(nper-1)*dble(i)
+         px(i) = rmax*cos(theta)
+         py(i) = rmax*sin(theta)
+      enddo
+
+      call plline(nper,px,py)
+
+      end
+
+C----------------------------------------------------------------------------
+C      Subroutine a2mnmx
+C      Minimum and the maximum elements of a 2-d array.
+
+      subroutine a2mnmx(f, nx, ny, fmin, fmax, xdim)
+      implicit none
+
+      integer   i, j, nx, ny, xdim
+      real*8    f(xdim, ny), fmin, fmax
+
+      fmax = f(1, 1)
+      fmin = fmax
+      do j = 1, ny
+        do  i = 1, nx
+          fmax = max(fmax, f(i, j))
+          fmin = min(fmin, f(i, j))
+        enddo
+      enddo
       end