diff --git a/code/read_parameter.f90 b/code/read_parameter.f90
index b1dd68e..dbbb736 100644
--- a/code/read_parameter.f90
+++ b/code/read_parameter.f90
@@ -19,3 +19,14 @@ subroutine read_real (x)
   WRITE(otape,*) cdum,x
 
 end subroutine read_real
+
+subroutine read_string (x)
+  use m_parameters
+
+  implicit none
+
+  character(len=*) :: x
+  READ(itape,*) cdum,x
+  WRITE(otape,*) cdum,x
+
+end subroutine read_string
diff --git a/code/sample/4pi-IC1/itape b/code/sample/4pi-IC1/itape
index cee1c54..ca6eb97 100644
--- a/code/sample/4pi-IC1/itape
+++ b/code/sample/4pi-IC1/itape
@@ -2,7 +2,7 @@
        l_0     4.   !3[pi]   
     int_pr     400
     tar_lo     0.60
-        dt     0.001 
+        dt     0.0005 
         sc     0.75
        vis     0.020           !2pi(162)ref  !2pi(256)mid  !2pi(256)Max !2p(162)Low
        pre     2.10E+4       !185.75          !185.75       !316.88       !440.5       !102.69
diff --git a/code/ysolve.f90 b/code/ysolve.f90
index 3f09f1b..1792a59 100644
--- a/code/ysolve.f90
+++ b/code/ysolve.f90
@@ -62,13 +62,21 @@
 
 !------------------------------------------------------------------------
 
+     REAL FUNCTION residual (x0, x1)
+
+       REAL, DIMENSION(:,:) :: x0, x1
+
+       residual = sum(abs(x0-x1))
+
+     END FUNCTION residual
+
      LOGICAL FUNCTION converged (x0, x1)
 
        REAL, DIMENSION(:,:) :: x0, x1
-       REAL :: residual = 0.
+       REAL :: r = 0.
 
-       residual = sum(abs(x0-x1))
-       converged = residual < absolute_tolerence
+       r = residual(x0 ,x1)
+       converged = r < absolute_tolerence
 
      END FUNCTION converged
 
@@ -78,6 +86,7 @@
 
       INTEGER :: i,j,k,savenum
       REAL :: pflame,pflold,delf=0.
+      REAL :: residue = 0.
 
       CALL SET_IC
 
@@ -88,6 +97,8 @@
 
        IF (t_now.ge.tf) EXIT
 
+       residue = residual(yold, y1)
+
        IF (converged(yold, y1)) EXIT
 
        ncyc=ncyc+1
@@ -117,9 +128,9 @@
          u=u+0.5*(hx*REAL(nx)*tar_lo-pflame)+0.5*(pflold-pflame)
          t_uf=0.
 
-         WRITE(*,'(a3,f8.3,a10,f6.3,a10,f6.3,a10,f7.4,a10,f7.4,a8,f7.4)') &
+         WRITE(*,'(a3,f8.3,a10,f6.3,a10,f6.3,a10,f7.4,a10,f7.4,a8,f7.4,a6,e10.4)') &
           ' T:',t_now,' // Tar_L:',l_0*tar_lo,' // cur_L:',pflame/hx/REAL(nx)*l_0, &
-          ' // Old_U:',oldu,' // New_U:',u(1),' // L_f:',delf
+          ' // Old_U:',oldu,' // New_U:',u(1),' // L_f:',delf,' // R:',residue
 
        ENDIF