I faced difficulty in a fortran error
Dear all,
I faced an error in fortran compiler: Divide by zero I found out the casue of that. However, I did not know a way to solve it. Here is a error.  KmT=475.0e6 KmD=155.0e3 CDT=2.36e10 CDD=2.57e10 C RENEW ATP CONCENTRATION AT BOTTOM WALL DO 510 I=1,L1 F_ATP=F(I,1,5)*VmaxT/(KmT*CDT)S/(CDT) F(I,1,5)=F(I,2,5)+F_ATP*YDIF(2) 510 CONTINUE C RENEW ADP CONCENTRATION AT BOTTOM WALL DO 520 I=1,L1 F_ADP=F(I,1,6)*VmaxD/(KmD*CDD)F(I,1,5)*VmaxT/(KmT*CDD) F(I,1,6)=F(I,2,6)+F_ADP*YDIF(2) 520 CONTINUE  As you can see, the values of KmT*CDT, CDT, KmD*CDD, and KmT*CDD is very small like the unit. How can I change them? I would be appreciated for this if you would help me. 
Re: I faced difficulty in a fortran error
Hi Kim....
Could you tell which, exactly, line is error ? Is it this line " F_ATP=F(I,1,5)*VmaxT/(KmT*CDT)S/(CDT)" or "F_ADP=F(I,1,6)*VmaxD/(KmD*CDD)F(I,1,5)*VmaxT/(KmT*CDD)"? If yes, It may because KmT or KmD is not define as REAL or DOUBLEPRECISION parameter. Normaly, FORTRAN define all parameter which has I,J,K,L,M,N in the first letter is INTEGER.So your KmT or KmD is ZERO. Hope this help.. STN 
Re: I faced difficulty in a fortran error
1) First to make sure that all you variables are declared with the appropriate type, add
implicit none at the first line of your routine. 2) Compute both dtmp0=KmT*CDT and dtmp1=KmT*CDD and before making the division, do a simple check on their value. Good luck. 
Re: I faced difficulty in a fortran error
Thanks really for your warm answer.
Like you gave me comment, I already did so. There is still error: Divied by zero.... Are there any solution? I will post the problem again.  ..... KmT=475.0e6 KmD=155.0e3 CDT=2.36e10 CDD=2.57e10 ..... DO 510 I=1,L1 F_ATP=F(I,1,5)*VmaxT/(KmT*CDT)S/(CDT) F(I,1,5)=F(I,2,5)+F_ATP*YDIF(2) 510 CONTINUE DO 520 I=1,L1 F_ADP=F(I,1,6)*VmaxD/(KmD*CDD)F(I,1,5)*VmaxT/KmT*CDD) F(I,1,6)=F(I,2,6)+F_ADP*YDIF(2) 520 CONTINUE   
Re: I faced difficulty in a fortran error
Hi, Kim:
Maybe your KmT, KmD and CDT are too small, and divition by a small number is apt to make errors. Can you normalize it first? Say, KmT_1=Kmt/1.0e6, KmD=KmD/1.0e3 ... Then you devide by (KmT_1*KmD) and times the result with 1.0e+9, hope this helps, wen 
Re: I faced difficulty in a fortran error
Dear J.Kim,
I´ve pasted your piece of code into my Fortran compiler (F90 for Windows) and with slight modifications (which I hope did not change the divison operation), it seemed to work (no divison by zero). Here is the small code I used: program kim implicit none real*8 KmT, KmD,CDT,CDD,F_ATP,F_ADP,S,VmaxD,VmaxT KmT=475.0e6 KmD=155.0e3 CDT=2.36e10 CDD=2.57e10 F_ATP=VmaxT/(KmT*CDT)S/(CDT) F_ADP=VmaxD/(KmD*CDD)F_ATP*VmaxT/(KmT*CDD) write(*,*) F_ATP,F_ADP,CDT pause end Obviously, I might have removed the source of error, but try it yourself. Best regards, Francisco. 
Re: Thanks for your good comment.

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