Thank you very much for your help.

[hasnaoui]

Thank you very much for your help.
but when I coming to run the stiffoptions.90 using the dvode_f90 subroutine, some errors appear like:

1982 | DVODE_F90(DERIVS,NEQ,Y,T,TOUT,ITASK,ISTATE,OPTIONS,J_FCN=JACD)
| 1

Error: There is no specific subroutine for the generic ‘dvode_f90’ at (1)
stiffoptions.f90:1985:78:

1985 | DVODE_F90(DERIVS,NEQ,Y,T,TOUT,ITASK,ISTATE,OPTIONS,J_FCN=JACS)
| 1

Error: There is no specific subroutine for the generic ‘dvode_f90’ at (1)
stiffoptions.f90:1988:78:

1988 | DVODE_F90(DERIVS,NEQ,Y,T,TOUT,ITASK,ISTATE,OPTIONS,J_FCN=JACB)
| 1

Error: There is no specific subroutine for the generic ‘dvode_f90’ at (1)

How to resolve these errors

thank you

 

[mikrom]

But that's the same problem as you asked here:

https://www.tek-tips.com/viewthread.cfm?qid=1816464

Add the missing INTENTs in the declaration of DERIVS

....
      SUBROUTINE DERIVS(NEQ,T,Y,YDOT)
!       Define the system derivatives.
        IMPLICIT NONE
        INTEGER NEQ
        DOUBLE PRECISION T, Y, YDOT
        DIMENSION Y(NEQ), YDOT(NEQ)
[highlight #FCE94F]        intent(in) :: NEQ, T, Y
        intent(out) :: YDOT        
[/highlight]        CALL FCN(T,Y,YDOT)
        RETURN
      END SUBROUTINE DERIVS