# CCL: Orca and float/double

*From*: Frank Neese <neese===thch.uni-bonn.de>
*Subject*: CCL: Orca and float/double
*Date*: Thu, 13 Nov 2008 20:26:38 +0100

Sent to CCL by: Frank Neese [neese#,#thch.uni-bonn.de]

I have yet another question with the ORCA input. I see no difference in
the timing or output from compressed double and float calculations (I am
working with 64 AMD machines).
These are the first lines of my input:
#Test a DFT calculation with cdouble
! RKS Quick-DFT cdouble
*xyz 1 1
#Test a DFT calculation with cfloat
! RKS Quick-DFT cfloat
*xyz 1 1
Is this the correct syntax (the program does not complain). I have also
tried the alternative input:
%SCF VALFORMAT COMPRESSION CFLOAT
end
But this gives an error.
Thanks again for your help. I have tried to contact the orca team but
they have not answered...
Regards,
Ramon

`
`

`that is the correct result: in SCF calculation it does not
matter since
``floats are never used (it would be deadly).
` It is MP2 where you see the difference.
Best regards,
FN

`PS: the syntax is not correct. You would have to use COMPRESSED and
``FLOAT as keywords in the simple input line and otherwise specifically
``assign the correct variables.
` --
---------------------------------------------------------------
Prof. Dr. Frank Neese
Lehrstuhl fuer Theoretische Chemie
Universitaet Bonn
Wegelerstr. 12
D-53115 Bonn, Germany
neese(-)thch.uni-bonn.de
Phone: +49-228-732351
FAX: +49-(0)228-739064
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