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Hello everybody!!


Hello everybody,

Mi name is Salomon and I'm a fortran user(This sounds
like AA meeting).
I'm new to the list and to fortran.
So far I've been able to construct some programs with
succes. However, rigth now I'm facing a problem that
simply goes far beyond my undestanding.

The problem I'm having is the following

I have a program that has to multiply matrices, one of
the matrices is symmetric and has the form

S = BT.C.B*detj + S

this matrix is in a do loop so it won't be symmetric
until the end of the cycle. BT is the transpose of B
and C is a 4*4 matrix. I've been playing with the
coeffients of C, they are of the order of 1e10. When I
use order of magnitude less than 1e9 the program works
just fine, I get my symmetric matrix, but with values
of 1e10 my result (S) is no longer symmetric. I tested
my code in Matlab and works perfect, it doesnt matter
the order of the coefficents of C.
I declared C as
REAL B(4,8)
REAl S(8,8)
REAL C(4,4)
REAL C11,C12,C13,C33,C44

I already tried REAL(4) and REAL(8) and nothing
happens. I use the gfortran compiler in linux.
Is there anything I'm missing??

Thanks for your help


	
	
		
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