C\$TEST TTGU3 c main program common /cstak/ ds real ds(350000) external handlu, bc, af integer ndx, ndy, istkgt, is(1000), iu integer nu, nr, iyb(3), ixb(3), kx, ky integer nxr(3), nyr(3), kxr(3), kyr(3) integer IUMB real errpar(2), rs(1000) logical ls(1000) complex cs(500) real tstart, dt, ws(500) real tstop equivalence (ds(1), cs(1), ws(1), rs(1), is(1), ls(1)) c to solve the layered heat equation, with kappa = 1, 1/2, 1/3, c div . ( kappa(x,y) * grad u ) = ut + g c the port library stack and its aliases. c initialize the port library stack length. call istkin(350000, 3) call enter(1) nu = 1 nr = 3 kx = 2 ky = 2 ndx = 3 ndy = 3 tstart = 0 tstop = 1 dt = 1 errpar(1) = 1e-2 errpar(2) = 1e-4 c uniform grid. ixb(1) = IUMB(0.0e0, 1.0e0, ndx, kx, nxr(1)) ixb(2) = IUMB(0.0e0, 1.0e0, ndx, kx, nxr(2)) ixb(3) = IUMB(0.0e0, 1.0e0, ndx, kx, nxr(3)) iyb(1) = IUMB(0.0e0, 1.0e0, ndy, ky, nyr(1)) iyb(2) = IUMB(1.0e0, 2.0e0, ndy, ky, nyr(2)) iyb(3) = IUMB(2.0e0, 3.0e0, ndy, ky, nyr(3)) c space for the solution. nnu=0 do 1 i=1,nr nnu=nnu+nu*((nxr(i)-kx)*(nyr(i)-ky)) 1 continue iu = istkgt(nnu, 3) do 2 i=1,nr kxr(i)=kx kyr(i)=ky 2 continue call SETR(nnu, 0.e0,ws(iu)) call ttgu(ws(iu),nu,nr,kxr,ws,nxr,ixb,kyr,ws,nyr,iyb,tstart, 1 tstop, dt, af, bc, errpar, handlu) call leave call wrapup stop end subroutine af(t, x, nx, y, ny, nu, u, ut, ux, uy, uxt, uyt 1 , a, au, aut, aux, auy, auxt, auyt, f, fu, fut, fux, fuy, fuxt, 2 fuyt) integer nu, nx, ny real t, x(nx), y(ny), u(nx, ny, nu), ut(nx, ny, nu), 1 ux(nx, ny, nu) real uy(nx, ny, nu), uxt(nx, ny, nu), uyt(nx, ny, nu), 1 a(nx, ny, nu, 2), au(nx, ny, nu, nu, 2), aut(nx, ny, nu, nu, 2) real aux(nx, ny, nu, nu, 2), auy(nx, ny, nu, nu, 2), 1 auxt(nx, ny, nu, nu, 2), auyt(nx, ny, nu, nu, 2), f(nx, ny, nu) 2 , fu(nx, ny, nu, nu) real fut(nx, ny, nu, nu), fux(nx, ny, nu, nu), fuy(nx, 1 ny, nu, nu), fuxt(nx, ny, nu, nu), fuyt(nx, ny, nu, nu) integer i, p, q real kappa logical temp do 7 i = 1, nu do 6 q = 1, ny do 5 p = 1, nx if (y(q) .ge. 1e0) goto 1 kappa = 1 goto 4 1 if (y(q) .ge. 2e0) goto 2 kappa = 0.5 goto 3 2 kappa = 1e0/3e0 3 continue 4 a(p, q, i, 1) = kappa*ux(p, q, i) aux(p, q, i, i, 1) = kappa a(p, q, i, 2) = kappa*uy(p, q, i) auy(p, q, i, i, 2) = kappa f(p, q, i) = ut(p, q, i) fut(p, q, i, i) = 1 f(p, q, i) = f(p, q, i)-y(q)/kappa temp = 1e0 .lt. y(q) if (temp) temp = y(q) .lt. 2e0 if (temp) f(p, q, i) = f(p, q, i)+1e0 temp = 2e0 .lt. y(q) if (temp) temp = y(q) .lt. 3e0 if (temp) f(p, q, i) = f(p, q, i)+3e0 5 continue 6 continue 7 continue return end subroutine bc(t, x, nx, y, ny, lx, rx, ly, ry, u, ut, ux, 1 uy, uxt, uyt, nu, b, bu, but, bux, buy, buxt, buyt) integer nu, nx, ny real t, x(nx), y(ny), lx, rx, ly real ry, u(nx, ny, nu), ut(nx, ny, nu), ux(nx, ny, nu) 1 , uy(nx, ny, nu), uxt(nx, ny, nu) real uyt(nx, ny, nu), b(nx, ny, nu), bu(nx, ny, nu, 1 nu), but(nx, ny, nu, nu), bux(nx, ny, nu, nu), buy(nx, ny, nu 2 , nu) real buxt(nx, ny, nu, nu), buyt(nx, ny, nu, nu) integer i, j logical temp do 6 j = 1, ny do 5 i = 1, nx temp = x(i) .eq. lx if (.not. temp) temp = x(i) .eq. rx if (.not. temp) goto 1 bux(i, j, 1, 1) = 1 c left or right. c neumann bcs. b(i, j, 1) = ux(i, j, 1) goto 4 1 if (y(j) .ne. ly) goto 2 b(i, j, 1) = u(i, j, 1) c bottom. bu(i, j, 1, 1) = 1 goto 3 2 b(i, j, 1) = u(i, j, 1)-6e0*t c top. bu(i, j, 1, 1) = 1 3 continue 4 continue 5 continue 6 continue return end subroutine ewe2(t, x, nx, y, ny, u, inu, ir) integer inu, ir, nx, ny real t, x(nx), y(ny), u(nx, ny), dble integer i, j c the exact solution. do 6 i = 1, nx do 5 j = 1, ny u(i, j) = (float(ir))*t*y(j)-(float(ir-1))*t if(ir.eq.3) u(i,j)=u(i,j)-t 5 continue 6 continue return end subroutine handlu(t0, u0, t, u, nv, dt, tstop) integer nv real t0, u0(nv), t, u(nv), dt, tstop common /a7tgup/ errpar, nu, mxp, myp integer nu real errpar(2) common /a7tgum/ kxp,ix,nxp,kyp,iy,nyp,nxnyt,nr,iup integer kx, ix, nx, ky, iy, ny common /cstak/is integer is(1000) iwrite=i1mach(2) if (t0 .ne. t) goto 2 write (iwrite, 1) t 1 format (16h restart for t =, 1pe10.2) return c get and print the error. 2 continue write(iwrite, 3)t 3 format(6h at t=,1pe10.2) ius=1 do 5 inu = 1, nu iyr=iy ixr=ix do 4 ir=1,nr ir1=ir-1 nx=is(nxp+ir1) ny=is(nyp+ir1) kx=is(kxp+ir1) ky=is(kyp+ir1) call gerr(kx, ixr, nx, ky, iyr, ny, u(ius), inu, t, ir) ixr=ixr+nx iyr=iyr+ny ius=ius+(nx-kx)*(ny-ky) 4 continue 5 continue return end subroutine gerr(kx, ix, nx, ky, iy, ny, u, inu, t, ir) integer kx, ix, nx, ky, iy, ny, inu, ir real u(1), t common /cstak/ ds real ds(500) integer ifa, ita(2), ixa(2), nta(2), nxa(2), ILUMD integer ixs, iys, nxs, nys, istkgt, i integer iewe, ka(2), ma(2), is(1000), i1mach real rs(1000) logical ls(1000) complex cs(500) real ABS, erru, AMAX1, ws(500) integer temp, temp1, temp2 equivalence (ds(1), cs(1), ws(1), rs(1), is(1), ls(1)) c to get and print the error at each time-step. c for variable inu for rectangle ir c u(nx-kx,ny-ky). c the port library stack and its aliases. call enter(1) c find the error in the solution at 2*kx * 2*ky points / mesh rectangle. c x search grid. ixs = ILUMD(ws(ix), nx, 2*kx, nxs) c y search grid. iys = ILUMD(ws(iy), ny, 2*ky, nys) c u search grid values. iewe = istkgt(nxs*nys, 3) c the exact solution. call ewe2(t, ws(ixs), nxs, ws(iys), nys, ws(iewe), inu, ir) ka(1) = kx ka(2) = ky ita(1) = ix ita(2) = iy nta(1) = nx nta(2) = ny ixa(1) = ixs ixa(2) = iys nxa(1) = nxs nxa(2) = nys ma(1) = 0 c get solution. ma(2) = 0 c approximate solution values. ifa = istkgt(nxs*nys, 3) c evaluate them. call tsd1(2, ka, ws, ita, nta, u, ws, ixa, nxa, ma, ws(ifa)) c error in solution values. erru = 0 temp = nxs*nys do 1 i = 1, temp temp2 = iewe+i temp1 = ifa+i erru = AMAX1(erru, ABS(ws(temp2-1)-ws(temp1-1))) 1 continue temp = i1mach(2) write (temp, 2) ir, inu, erru 2 format(9h for rect,i3,14h error in u(.,, i2, 1 3h) =, 1pe10.2) call leave return end