libsim Versione 7.2.6
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◆ fp_q
quad precision floating point (16 byte IEEE) if supported, otherwise double precision floating point Definizione alla linea 262 del file kinds.F90. 262! Copyright (C) 2010 ARPA-SIM <urpsim@smr.arpa.emr.it>
263! authors:
264! Davide Cesari <dcesari@arpa.emr.it>
265! Paolo Patruno <ppatruno@arpa.emr.it>
266
267! This program is free software; you can redistribute it and/or
268! modify it under the terms of the GNU General Public License as
269! published by the Free Software Foundation; either version 2 of
270! the License, or (at your option) any later version.
271
272! This program is distributed in the hope that it will be useful,
273! but WITHOUT ANY WARRANTY; without even the implied warranty of
274! MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
275! GNU General Public License for more details.
276
277! You should have received a copy of the GNU General Public License
278! along with this program. If not, see <http://www.gnu.org/licenses/>.
279#include "config.h"
280!> \defgroup base Libsim package, base library.
281!! The libsim base library defines modules and classes of general
282!! use for scientifical applications in Fortran 90. In order to
283!! compile and link programs using this library, you have to insert
284!! the required \c USE statements in the program units involved,
285!! specify the location of module files when compiling (tipically \c
286!! -I/usr/lib/gfortran/modules or \c -I/usr/lib64/gfortran/modules or
287!! \c -I/usr/include) and indicate the library name \c -lsim_base when
288!! linking, assuming that the library has been installed in a default
289!! location.
290
291!> Definition of constants to be used for declaring variables of a
292!! desired type. This module defines constants that can be portably
293!! used when declaring variables (through the \c KIND attribute) and
294!! when defining constants (through the underscore character \c _ ) in
295!! order to be sure that the desired type is used.
296!!
297!! There is a subtle difference between platform-default single and
298!! double precision real, obtained by declaring a variable of type \c
299!! REAL or \c DOUBLE \c PRECISION respectively, and single and double
300!! precision IEEE (4 and 8 bytes respectively) which are the standard
301!! IEEE data types and which are declared through \c REAL(kind=fp_s)
302!! and \c REAL(kind=fp_d) respectively: these two pairs of types
303!! usually coincide, but it may be not the case on some platforms, so
304!! you should choose one or the other approach depending on situation.
305!!
306!! Example of typical use:
307!! \code
308!! USE kinds
309!! ...
310!! INTEGER(kind=int_b) :: ab, bb
311!! REAL(kind=fp_d) :: dd
312!!
313!! ab = 13_int_b
314!! dd = REAL(ab, kind=fp_d)
315!! ...
316!! \endcode
317!! \ingroup base
319IMPLICIT NONE
320
321INTEGER, PARAMETER :: int_b = selected_int_kind(1) !< 1-byte integer (byte)
322INTEGER, PARAMETER :: int_s = selected_int_kind(4) !< 2-byte integer (short)
323INTEGER, PARAMETER :: int_l = selected_int_kind(8) !< 4-byte integer (long)
324INTEGER, PARAMETER, PRIVATE :: &
325 int_ll_t = selected_int_kind(16)
326!> 8-byte integer (long long) if supported, otherwise 4-byte integer
327INTEGER, PARAMETER :: int_ll = &
328 ( ( ( 1 + sign( 1, int_ll_t ) ) / 2 ) * int_ll_t ) + &
329 ( ( ( 1 - sign( 1, int_ll_t ) ) / 2 ) * int_l )
330
331INTEGER, PARAMETER :: fp_s = selected_real_kind(6) !< single precision floating point (4 byte IEEE)
332INTEGER, PARAMETER :: fp_d = selected_real_kind(15) !< double precision floating point (8 byte IEEE)
333INTEGER, PARAMETER, PRIVATE :: fp_q_t = selected_real_kind(20)
334!> quad precision floating point (16 byte IEEE) if supported, otherwise double precision floating point
335INTEGER, PARAMETER :: fp_q = &
336 ( ( ( 1 + sign( 1, fp_q_t ) ) / 2 ) * fp_q_t ) + &
337 ( ( ( 1 - sign( 1, fp_q_t ) ) / 2 ) * fp_d )
338
339INTEGER, PARAMETER :: ptr_c = sizeof_ptr_c !< kind for an integer having the same size of a C pointer
340
Definition of constants to be used for declaring variables of a desired type. Definition kinds.F90:245 |