2. The functions provided and their use#

2.1. Generality#

To help with the use of these functions, an effort has been made to codify the names of the functions using three components:

nature GGde greatness:
- LB length in bits,
- LO length in bytes,
- MA maximum positive value,
- MI minimum positive value,
- GA value range.
The TT type of the size to which it applies:
- IS INTEGER (integer),
- LS LOGICAL (logical),
*R8 REAL*8 (real),

*C8 COMPLEX*8 (complex).
The EM suffix (Machine Environment).

For length parameters (l_) the functions are of integer type. Function names are of the form: GGTTEM.

For parameters whose value depends on the type, the type of the function will be that of the value sought. In this case the function names are of the form: TTGGEM.

Since these functions are not part of the intrinsic functions of the language, it is essential to declare their type in each user program unit.

2.2. Logical type#

Standard logic type (LOGICAL)

Type of function	Parameter provided	Function ENVIMA	64-bit platform	32-bit platform
INTEGER	Length in bytes	LOLSEM	8	4

2.3. Integer type#

Standard integer type (INTEGER)

Type of function	Parameter provided	Function ENVIMA	64-bit platform	32-bit platform
INTEGER	Length in bytes	LOISEM	8	4
INTEGER	Maximum value	ISMAEM	formula \({2}^{63}-1\)	formula \({2}^{31}-1\)	formula 2147483647

2.4. Real type#

*Standard real type (REAL*8)

Type of function	Parameter provided	Function ENVIMA	64-bit platform	32-bit platform
REAL *8	Relative Accuracy	R8 PREM	2.220D-16	2.220D-16	2.220D-16
REAL *8	Maximum Value	R8 MAEM	1.798D+308	1.798D+308
REAL *8	Minimum value	R8 MIEM	2.225D-308	2.225D-308	2.225D-308
REAL *8	Range	R8 GAEM	1.340D+154	1.340D+154

2.5. File usage settings#

These settings are used because of operational constraints on servers whose resources are shared. The databases (glob.i and vola.i files) are generally created on a limited shared space (/tmp).

Type of function	Parameter provided	Function ENVIMA	64-bit platform	32-bit platform
INTEGER	Maximum file length in bytes	LOFIEM	12582912	2048000
INTEGER	Cumulative file size in bytes	MOFIEM	50331648	50331648	50331648

2.6. Assigning binary constants#

To build masks on digital information, it is necessary to quickly access bit weights. These can be accessed by the integer function ISPBEM (bit number).

ISPBEM (4) = 0000000000000000000000001000 = \({2}^{4\mathrm{-}1}\) = 8

2.7. Assignment of mathematical or physical constants#

The particular constants are accessible from the type of the requested variable:

Type of function	Parameter provided	Function ENVIMA	Value
REAL *8	\(\pi\)	R8PI	3.141592653589793D+00
REAL *8	\(2\pi\)	R8 DEPI	6.283185307179586D+00
REAL *8	Radian/degree conversion	R8 DGRD	1.745329251994330D-02
REAL *8	Degree/Radian Conversion	R8 RDDG	5.729577951308232D+01
REAL *8	Absolute zero (temperature)	R8T0	273.15

2.8. Special values#

These values are available on all machines with IEEE arithmetic.

Type of function	Parameter provided	Function ENVIMA	Value
INTEGER	Value that caused an error during a float operation	ISNNEM
REAL *8	Value that caused an error during a float operation	R8 NNEM	NaN
REAL *8	Data structure initialization value	R8 VIDE	1.797693134862316+308

2.9. Utility#

The Fortran IMPVEM subroutine makes it possible to globally edit the various characteristic values of the processing machine on the file with the logical unit number IUL. An example is given in the appendix.

CALL IMPVEM (IUL): Print all the characteristics of the standard types.

2.10. Precautions for use#

Since these functions are not part of the intrinsic functions of the language, it is essential to declare their type in each user program unit. In this case the function names are TTGGEM with TT type of the function and GG nature of the quantity (cf. example of use).

Note:

Values for integers are of the implicit integer type (functions starting with a letter L- or N-) .

<limits.h><float.h>The ENVIMA functions are available in the Code_Aster C utility library, and are mostly based on the standard C libraries: header files and [bib4].

By definition, any operation to port a subset of Code_Aster to other hardware requires the prior port of ENVIMA. The use of standard headers significantly limits a thorough search of the manufacturer’s documentation.