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EES 64-Bit Professional Version


The Commercial and Professional versions of EES are 32-bit Windows executable programs that are designed to operate on 32-bit or 64-bit Windows operating systems, such as Windows XP, Windows Vista, Windows 7 and Windows 8.  There is now also a true 64-bit version of EES (EES64.exe) that will only work on 64-bit operating systems.  The 64-bit Professional version operates in exactly the same manner as the 32-bit Professional version except that it calculates faster and it allows a maximum of 24,000 variables, compared to 12,000 variables in the 32-bit Professional version.  Calculation speeds for the 64-bit version can be a factor of 2 to 3 times faster than the 32-bit version for computationally-intensive problems.   The files written by the 64-bit version have a different format than the corresponding files written with the 32-bit version, which necessitates the use of the additional 64 in the file name extensions. This page summarizes the important differences between the 32 and 64-bit versions.  


The 64-bit version requires a 64-bit Windows operating system, e.g., Windows 7/8 64 bit.  It will not work on a 32-bit operating system.


A 64-bit license (EES.DFT64) file is required to run the 64-bit version.  This file can be purchased from our Order page.  Note that a Professional license with a current subscription to Instant Update and Technical Support (IUTS) service is required in order to obtain a 64-bit license file.


There is only a 64-bit Professional version.  A Commercial license will not be able to run the 64-bit version.


The 64-bit version saves EES files with the .EES64 file name extension.  EES64 files are identified by the file name extension and the yellow EES 64 icon.  Double-clicking on an EES64 file will start the 64-bit version of EES.  The 32-bit version of EES cannot read .EES64 files.    


The 32-bit versions of EES do all floating point calculations using extended floating point numbers having 80 bits of numerical precision.  The 64-bit version uses doubles, which are floating point numbers having 64 bits of precision.  As a result, the 32-bit version provides greater precision and allows larger numerical values than the 64-bit version.  The largest number that the 64-bit version can handle is approximately 1.7E308.   The use of 64-bit doubles is the major reason that the 64-bit version calculates faster than the 32-bit version.


Library files in the 64-bit version are saved with the .LIB64 file name extension.  Similarly, EES Lookup files, external functions and procedures are identified with a 64 in the file name extension, e.g., LKT64, .FDL64, .DLF64, and .DLP64.  None of these files can be read by the 32-bit version because of the different format of the floating point numbers.


The native form for binary Lookup table files in the 64-bit version of EES is .LKT64.


The 64-bit version of EES can read any 32-bit or 64-bit .EES, .LIB file or .LKT file.  However, it is necessary to convert the information in the 32-bit file to equivalent 64-bit information and this conversion process can be slow for large files.  After reading a 32-bit file, save it as 64-bit file so that is will be read quickly the next time it is opened.


The 64-bit version can save all EES, Library and Lookup tables files in a format that can be read by the 32-bit Commercial and Professional versions.  EES is programmed to save files in the 32-bit format if the file name extension is .EES or .LIB instead of .EES64 or .LIB64.  The Open and Save As dialogs provide a dropdown control to select various file types, including the 32-bit formats.


The 64-bit version can not read external library files (.FDL, .DLP, .DLF, .DLL) that were created for the 32-bit version. It is necessary to recompile these external library files with a 64-bit compiler and save them with  .FDL64, .DLP64, .DLF64, and .DLL64 file name extensions.  


Library files (.LIB64, .FDL64, .DLF64, .DLP64 and .DLL64) are automatically loaded when the 64-bit EES program is started if they are placed in the USERLIB64 folder.


The EES_REFPROP interface (EES_REFPROP.DLL) must be upgraded to operate with the 64-bit version.  The upgrade can be ordered from our Order page.