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man pages->IRIX man pages -> f90/epsilon (3)
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### Contents

```
EPSILON(3I)					       Last changed: 1-6-98

```

### NAME[Toc][Back]

```     EPSILON - Returns a positive number near 1	in the numeric model
```

### SYNOPSIS[Toc][Back]

```     EPSILON ([X=]x)
```

### IMPLEMENTATION[Toc][Back]

```     UNICOS, UNICOS/mk,	and IRIX systems
```

### STANDARDS[Toc][Back]

```     Fortran 90
```

### DESCRIPTION[Toc][Back]

```     The EPSILON intrinsic function returns a positive model number that is
almost negligible compared	to unity in the	model representing numbers
of	the same type and kind type parameter as the argument.	It accepts
the following argument:

x	Must be	of type	real.  It can be scalar	or array valued.

EPSILON is	an inquiry function.  The name of this intrinsic cannot	be
passed as an argument.
```

### RETURN VALUES[Toc][Back]

```     The result	type is	a scalar of the	same type and kind type	parameter
as	x.  The	result has the value
(1-p)
b	    where b and	p are as defined in the	model for real numbers
representing numbers of the same type and kind type parameter as x.
For information on	the real number	model, see the MODELS(3I) man page.
```

### EXAMPLES[Toc][Back]

```     The following code	fragment was run on several systems:

REAL(KIND=4) r4
REAL(KIND=8) r8
REAL(KIND=16)	r16
REAL rd
PRINT	*,'EPSILON r4=',EPSILON(r4)
PRINT	*,'EPSILON r8=',EPSILON(r8)
PRINT	*,'EPSILON r16=',EPSILON(r16)
PRINT	*,'EPSILON rd=',EPSILON(rd)
END

The results of this test case on IRIX systems are as follows:

EPSILON r4= 1.192092896E-7
EPSILON r8= 2.22044604925031308E-16
EPSILON r16= 1.23259516440783094595582588325435348E-32
EPSILON rd= 1.192092896E-7

The results of this test case on CRAY T90 systems that support IEEE
floating-point arithmetic are as follows:

EPSILON r4= 1.192092896E-7
EPSILON r8= 2.22044604925031308E-16
EPSILON r16= 1.92592994438723585305597794258492732E-34
EPSILON rd= 2.22044604925031308E-16

The results of this test case on UNICOS systems, except for CRAY T90
systems that support IEEE floating-point arithmetic, are as follows:

EPSILON r4= 1.192092895507812E-7
EPSILON r8= 1.4210854715202E-14
EPSILON r16= 5.04870979341447555463506281781E-29
EPSILON rd= 1.4210854715202E-14

The results of this test case on UNICOS/mk	systems	are as follows:

EPSILON r4= 1.192092896E-7
EPSILON r8= 2.22044604925031308E-16
EPSILON r16= 2.22044604925031308E-16
EPSILON rd= 2.22044604925031308E-16
```

```     MODELS(3I)

Intrinsic Procedures Reference Manual, publication	SR-2138, for the
printed version of	this man page.

EPSILON(3I)					       Last changed: 1-6-98

```

### NAME[Toc][Back]

```     EPSILON - Returns a positive number near 1	in the numeric model
```

### SYNOPSIS[Toc][Back]

```     EPSILON ([X=]x)
```

### IMPLEMENTATION[Toc][Back]

```     UNICOS, UNICOS/mk,	and IRIX systems
```

### STANDARDS[Toc][Back]

```     Fortran 90
```

### DESCRIPTION[Toc][Back]

```     The EPSILON intrinsic function returns a positive model number that is
almost negligible compared	to unity in the	model representing numbers
of	the same type and kind type parameter as the argument.	It accepts
the following argument:

x	Must be	of type	real.  It can be scalar	or array valued.

EPSILON is	an inquiry function.  The name of this intrinsic cannot	be
passed as an argument.
```

### RETURN VALUES[Toc][Back]

```     The result	type is	a scalar of the	same type and kind type	parameter
as	x.  The	result has the value
(1-p)
b	    where b and	p are as defined in the	model for real numbers
representing numbers of the same type and kind type parameter as x.
For information on	the real number	model, see the MODELS(3I) man page.
```

### EXAMPLES[Toc][Back]

```     The following code	fragment was run on several systems:

REAL(KIND=4) r4
REAL(KIND=8) r8
REAL(KIND=16)	r16
REAL rd
PRINT	*,'EPSILON r4=',EPSILON(r4)
PRINT	*,'EPSILON r8=',EPSILON(r8)
PRINT	*,'EPSILON r16=',EPSILON(r16)
PRINT	*,'EPSILON rd=',EPSILON(rd)
END

The results of this test case on IRIX systems are as follows:

EPSILON r4= 1.192092896E-7
EPSILON r8= 2.22044604925031308E-16
EPSILON r16= 1.23259516440783094595582588325435348E-32
EPSILON rd= 1.192092896E-7

The results of this test case on CRAY T90 systems that support IEEE
floating-point arithmetic are as follows:

EPSILON r4= 1.192092896E-7
EPSILON r8= 2.22044604925031308E-16
EPSILON r16= 1.92592994438723585305597794258492732E-34
EPSILON rd= 2.22044604925031308E-16

The results of this test case on UNICOS systems, except for CRAY T90
systems that support IEEE floating-point arithmetic, are as follows:

EPSILON r4= 1.192092895507812E-7
EPSILON r8= 1.4210854715202E-14
EPSILON r16= 5.04870979341447555463506281781E-29
EPSILON rd= 1.4210854715202E-14

The results of this test case on UNICOS/mk	systems	are as follows:

EPSILON r4= 1.192092896E-7
EPSILON r8= 2.22044604925031308E-16
EPSILON r16= 2.22044604925031308E-16
EPSILON rd= 2.22044604925031308E-16
```

```     MODELS(3I)