ERROR IN BIG NUMBERS

[baharengineer]

i have some line of code like :
VEC(1)=0.0
VEC(2)=0.0
DO 5 I=3,MM5
5 VEC(I)=1.0/1.E50
ITRY=0
15 CONTINUE
ITRY=ITRY+1
AMAX=0.0
DO 25 I=1,MM5
A(I)=0.0
DO 20 J=1,MM5
20 A(I)=A(I)+VEC(J)*CMAT(I,J)
IF(ABS(A(I)).GT.ABS( AMAX)) AMAX=A(I)
25 CONTINUE
DO 30 I=1,MM5
A(I)=A(I)/AMAX
30 CONTINUE
IF(ITRY.EQ.4) GO TO 100
DO 40 I=1,MM5
40 VEC(I)=A(I)/1.E50
GO TO 15

that program has error after run because E50 and has error for over or under flow !

why i have error? i compile via compaq visual fortran 6.6

and i have some line like this:
ISCALE=0
R1=10.0**100
R2=1.0/R1
that line **100 has warning for overflow too

whether i cannot have big number in visual fortran ?
my program language is fortran IV!!!

please tell me how can i fix this
thx

 

[baharengineer]

sorry i forget : in my program vec is defined like this:

DIMENSION VEC(5)

 

[NickFort]

I think xwb is probably a lot more qualified to attempt to figure out what's going on there (I don't know "vintage" Fortrans, or as much as he* does about Fortran in general), but here's the general trend I'm seeing in this code you keep posting: it seems like it was all written by someone else, and badly! Or at least, so that much of it isn't easily compilable nowadays. Where and when it compiled, I don't know, but is it worth the hassle of having to (seemingly) change every third line of it?

* "he" presumably.

--------------------------------------
Background: Chemical engineer, familiar mostly with MATLAB, but now branching out into real programming.

 

[baharengineer]

YES this program write by nasa in 1987

and i must correctly execution this

this is my job now

i have a project on that

and this program has output , there is pdf of documentation on nasa!!!

this is error that i get

(1513) : Warning: Overflow occurred while evaluating constant expression.