Something very strange

[halleluja]

Hi everyone,

i have written a subroutine, but i found something very strange.
If i add this code

Code: [Select]

         print*,'foundus6',foundus6 
to my subroutine, it works fine.

If i didn't add this code , i got this

Code: [Select]

*ERROR* Residual norm is NaN or Inf
Note: The following floating-point exceptions are signalling: IEEE_INVALID_FLAG IEEE_DIVIDE_BY_ZERO IEEE_UNDERFLOW_FLAG IEEE_DENORMAL


It is strange that the print function has influence on the code if it works fine.

[halleluja]

Here foundus6 is a logical type data:

Code: [Select]

      logical foundus6

[Prof. R.L. Taylor]

When you add a print statement you cause the compiler to change the way it produces the final executable.

You have a bug somewhere, a dimension error probably.  You can use the debugger to find where it is -- first carefully check your program.

You can also post your routine for users to check.

[halleluja]

Dear Prof. R.L. Taylor,

thanks a lot for your reply.

But if i change

Code: [Select]

        print*,'foundus6',foundus6 to

Code: [Select]

        print*,'foundus6', it still dosen't work, even though with a print statement here.

[Prof. R.L. Taylor]

This is typical.  You have a bug somewhere!

[halleluja]

Alright i will try to debug first. Thanks.

[Prof. S. Govindjee]

Valgrind and GDB will be your friends here.

[halleluja]

Dear Prof. S. Govindjee,

is it possible that you make an example how gdb works on feap like your video how man install feap. I think this will help a lot feap users.


Best wishes

[Prof. S. Govindjee]

A video on how to use GDB is perhaps a pretty big undertaking.  The best thing to do is to locate someone local that uses it to show you how it works on an elementary level, for example a computer science student.

For valgrind you can try running the following but beware that there will lots of output and you will have to wade through it carefully.

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valgrind -v --leak-check=full --show-reachable=yes feap


[JStorm]

There are explainations available at www, also as video like https://www.youtube.com/watch?v=bWH-nL7v5F4.
FEAP is nothing special whyile using GDB. Make sure you compile with debugging flag "-g" and without optimization "-O0".

[Prof. S. Govindjee]

The no-optimization recommendation is tricky.  Sometimes the problem with a program is the optimization assumptions of the compiler.  If this is the case, then you need to debug at the optimization level at which the error appears.  Of course if the error you wish to debug appear in -O0, then that will be the easier way to go.