IDL Reference Guide: Procedures and Functions

CEIL

The CEIL function returns the closest integer greater than or equal to its argument.

Syntax

Result = CEIL(X [, /L64] )

Return Value

If the input value X is integer type, Result has the same value and type as X. Otherwise, Result is a 32-bit longword integer with the same structure as X.

Arguments

X

The value for which the ceiling function is to be evaluated. This value can be any numeric type (integer, floating, or complex).

Keywords

L64

If set, the result type is 64-bit integer regardless of the input type. This is useful for situations in which a floating point number contains a value too large to be represented in a 32-bit integer.

Thread Pool Keywords

This routine is written to make use of IDL's thread pool, which can increase execution speed on systems with multiple CPUs. The values stored in the !CPU system variable control whether IDL uses the thread pool for a given computation. In addition, you can use the thread pool keywords TPOOL_MAX_ELTS, TPOOL_MIN_ELTS, and TPOOL_NOTHREAD to override the defaults established by !CPU for a single invocation of this routine. See Thread Pool Keywords for details.

Examples

To print the ceiling function of 5.1, enter:

PRINT, CEIL(5.1)  
; IDL prints:  
6  

To print the ceiling function of 3000000000.1, the result of which is too large to represent in a 32-bit integer:

PRINT, CEIL(3000000000.1D, /L64)  
; IDL prints:  
3000000001