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3.3 Dynamic arrays management utilities

The utilities are described alphabetically in this section.

Essentially, the programmer initializes the super-array with the aid of utility INITIS (p. ), allocates dynamic arrays with READRE, and frees them with TUER. The uniqueness of each array name (parameter TAB) is the programmer's responsibility.

Utility IMATAB

SUBROUTINE IMATAB( )

INTEGER M(*)

This utility prints the list of all the dynamic arrays allocated in M.

Utility MAXTAM

SUBROUTINE MAXTAM( , , )

INTEGER M(*), IATAB, LTAB

This utility determines the maximum size that can be allocated.

Warning: MAXTAM does not reserve the memory space found. The habitual use takes the following form:

      ...
C --- DETERMINE THE MAXIMUM SIZE THAT CAN BE ALLOCATED
      CALL MAXTAM(M, IATAB, LMAX)
C --- ALLOCATE AN ARRAY WITH THE MAXIMUM LENGTH
      NTYTAB = ...
      TAB = ...
      CALL READRE(NTYTAB, TAB, IATAB, LMAX, M, ICODE)
C --- USE THIS ARRAY
      ...
C --- DETERMINE THE SIZE ACTUALLY USED
      LTAB = ...
C --- ADJUST THE SIZE OF THE ARRAY
      CALL READRE(NTYTAB, TAB, IATAB, LTAB, M, ICODE)
      ...

Remark: when several large arrays must be allocated, it is necessary to call MAXTAM several times:

      ...
C ALLOCATE TWO LARGE ARRAYS WITH SIMILAR LENGTHS
      CALL MAXTAM(M, IAT1, LMAX)
      CALL READRE(1, 'T1', IAT1, LMAX/2, M, ICODE)
      CALL MAXTAM(M, IAT2, LMAX)
      CALL READRE(2, 'T2', IAT2, LMAX, M, ICODE)
      ...

Utility READRE

SUBROUTINE READRE( , , , , , )

INTEGER NTYTAB, IATAB, LTAB, M(*), ICODE

CHARACTER*(*) TAB

This utility allocates an array (the elements of this array are not initialized).

On exit, ICODE equals 1 if the array existed with the same length and type, 0 if not.

If LTAB = 0, no array is allocated, but on exit IATAB = 1. In fact, if IATAB was not initialized, passing M(IATAB) as a parameter may result in an execution error.

If the super-array does not contain an array with the same name, the allocation should not pose any difficulty. On the other hand, if an array with the same name exists already, it is "re-allocated" in the following manner:

Let NTYTAB be the type requested, NTYTAB be the type of the old array, LTAB be the length requested, and LTAB be the length of the old array.

• If NTYTAB NTYTAB, then the old array is deleted and the new array is allocated.

• If NTYTAB = NTYTAB, then LTAB is compared to LTAB:
  • If LTAB < LTAB, then the length is adjusted.
  • If LTAB > LTAB, then the old array is deleted and the new one allocated. (Warning: the contents is not copied into the new array.)
  • If LTAB = LTAB, then no array is allocated as the old one is correct.

Utility RENOMM

SUBROUTINE RENOMM( , , , , )

CHARACTER*(*) OLDTAB, NEWTAB

INTEGER IATAB, LTAB, M(*)

This utility renames an array, where

OLDTAB

is the old name of the array, and

NEWTAB

is the new name.

Warning: Errors are possible if OLDTAB and NEWTAB do not have the same number of characters.

Utility TROUVE

SUBROUTINE TROUVE( , , , , , )

INTEGER NTYTAB, IATAB, LTAB, ICODE, M(*)

CHARACTER*(*) TAB

This utility performs an array search by name. If the array is found, the exit parameters are updated. If not, IATAB = 0 on exit.

Parameter ICODE is only conserved for the sake of compatibility.

Remark: In principle, the programmer must conserve the address, IATAB, returned by READRE and avoid to call TROUVE (but it is not always possible!).

Utility TUER

SUBROUTINE TUER( , )

CHARACTER*(*) TAB

INTEGER M(*)

This utility frees an array (the space freed becomes available for a new allocation). For example, at the end of a module all work arrays must be deleted in this manner.

Utility TYPCLA

SUBROUTINE TYPCLA( , , )

INTEGER NTYTAB, NM1, NM2

This utility returns the type, NTYTAB, of an array using two integers, NM1 and NM2 (print using the Fortran format: 2A4):

ENTIER, REEL1MOT, LOGIQUE, CARACTER, REEL2MOT,
COMPLEXE, COMPLEX2.

Utility TYPMOT

SUBROUTINE TYPMOT( , )

INTEGER NTYTAB, NBREMO

This utility returns the number of words occupied by an element of an array of type NTYTAB. For example: NTYTAB returns NBREMO = 1, NTYTAB = 5 returns NBREMO = 2, ...