IRIX Base Documentation 2002 November/SGI IRIX Base Documentation 2002 November.iso/usr/share/catman/p_man/cat3/f90/eoshift.z/eoshift

Text File | 2002-10-03 | 5.8 KB | 131 lines

EOSHIFT(3I)                                           Last changed: 4-13-99


NNAAMMEE
     EEOOSSHHIIFFTT - Performs an end-off shift on an array expression

SSYYNNOOPPSSIISS
     EEOOSSHHIIFFTT (([AARRRRAAYY==]_a_r_r_a_y,, [SSHHIIFFTT==]_s_h_i_f_t [,,[BBOOUUNNDDAARRYY==]_b_o_u_n_d_a_r_y]
     [,,[DDIIMM==]_d_i_m]))

IIMMPPLLEEMMEENNTTAATTIIOONN
     UNICOS, UNICOS/mk, IRIX systems

     CF90, MIPSpro 7 Fortran 90

SSTTAANNDDAARRDDSS
     Fortran

DDEESSCCRRIIPPTTIIOONN
     The EEOOSSHHIIFFTT intrinsic function performs an end-off shift on an array
     expression of rank one, or it performs end-off shifts on all the
     complete rank one sections along a given array expression of rank two
     or greater.  Elements are shifted off at one end of a section and
     copies of a boundary value are shifted in at the other end.  Different
     sections can have different boundary values and can be shifted by
     different amounts and in different directions; positive for left
     shifts, negative for right shifts.

     EEOOSSHHIIFFTT accepts the following arguments:

     _a_r_r_a_y     May be of any type.  It must not be scalar.

     _s_h_i_f_t     Must be integer.  If _a_r_r_a_y has rank one, _s_h_i_f_t must be a
               scalar.  Otherwise, _s_h_i_f_t must be scalar or have rank _n-1
               and have
               shape (_d , _d , ..., _d     , _d     , ..., _d ),
                       1   2        _d_i_m-1   _d_i_m+1        _n
               where (_d , _d , ..., _d )
                       1   2        n
               is the shape of _a_r_r_a_y.

     _b_o_u_n_d_a_r_y  Must be of the same type and have the same type parameters
               as _a_r_r_a_y.  Must be scalar if _a_r_r_a_y has rank one; otherwise,
               it must be either scalar or of rank _n-1 and of
               shape (_d , _d , ..., _d     , _d     , ..., _d ),
                       1   2        _d_i_m-1   _d_i_m+1        _n
               The _b_o_u_n_d_a_r_y argument can be omitted for the data types in
               the following list.  In these cases, the default value is
               the scalar value shown:

               TTyyppee ooff _a_r_r_a_y       DDeeffaauulltt VVaalluuee ooff _b_o_u_n_d_a_r_y

               Integer             0

               Real                0.0

               Complex             (0.0,0.0)

               Logical             false

               Character(_l_e_n)      _l_e_n blanks

               The _b_o_u_n_d_a_r_y data type must be present for derived data
               types.

     _d_i_m       Must be a scalar.  Must be an integer value in the range
               1 <= _d_i_m <= _n, where _n is the rank of _a_r_r_a_y.  If _d_i_m is
               omitted, the default value is 1.

     EEOOSSHHIIFFTT is a transformational intrinsic function.  The name of this
     intrinsic cannot be passed as an argument.

RREETTUURRNN VVAALLUUEESS
     The result is an array of the same type, type parameters, and shape as
     _a_r_r_a_y.

     Element (_s , _s , ..., _s )
               1   2        _n
     of the result has the value
     _a_r_r_a_y(_s , _s , ..., _s     , _s    + _s_h, _s     , ..., _s ),
            1   2        _d_i_m-1   _d_i_m        _d_i_m+1        _n
     where _s_h is _s_h_i_f_t or
     _s_h_i_f_t(_s , _s , ..., _s     , _s     , ..., _s ),
            1   2        _d_i_m-1   _d_i_m+1        _n
     provided that the inequality
     LLBBOOUUNNDD((_a_r_r_a_y,_d_i_m) <= _s    + _s_h <= UUBBOOUUNNDD((_a_r_r_a_y,_d_i_m)
                           _d_i_m
     holds and is otherwise _b_o_u_n_d_a_r_y or
     _b_o_u_n_d_a_r_y(_s , _s , ..., _s     , _s     , ..., _s ).
               1   2        _d_i_m-1   _d_i_m+1        _n

EEXXAAMMPPLLEESS
     Example 1:  If VV is an array [[11,, 22,, 33,, 44,, 55,, 66]], the effect of
     shifting VV end-off to the left by three positions is achieved by
     EEOOSSHHIIFFTT((VV,, SSHHIIFFTT == 33)), which has the value [[44,, 55,, 66,, 00,, 00,, 00]].
     Specifying EEOOSSHHIIFFTT((VV,, SSHHIIFFTT == --22,, BBOOUUNNDDAARRYY == 9999)) achieves an end-off
     shift to the right by two positions with the boundary value of 9999 and
     has the value of [[9999,, 9999,, 11,, 22,, 33,, 44]].

     Example 2:  The rows of an array of rank two can all be shifted by the
     same amount or by different amounts and the boundary elements can be
     the same or different.  Assume that MM is the following array:

          | A B C |
          | D E F |
          | G H I |

     The value of EEOOSSHHIIFFTT((MM,, SSHHIIFFTT ==--11,, BBOOUUNNDDAARRYY == ''**'',, DDIIMM == 22)) is as
     follows:

          | * A B |
          | * D E |
          | * G H |

     The value of EEOOSSHHIIFFTT((MM,, SSHHIIFFTT ==((// --11,, 11,, 00 //)),, BBOOUUNNDDAARRYY == ((// ''**'',, ''//'',,
     ''??'' //)),, DDIIMM == 22)) is as follows:

          | * A B |
          | E F / |
          | G H I |

     The value of section EEOOSSHHIIFFTT((MM((22::33,,22::33)),, SSHHIIFFTT == --11,, BBOOUUNNDDAARRYY == ''**'',,
     DDIIMM==22)) is as follows:

          | * E |
          | * H |

SSEEEE AALLSSOO
     _I_n_t_r_i_n_s_i_c _P_r_o_c_e_d_u_r_e_s _R_e_f_e_r_e_n_c_e _M_a_n_u_a_l for the printed version of this
     man page.