for_op (nst man page)

NAME

for_op -- unit to iterate operands

PROTOTYPE

unitptr for_op( int nu, int ni, char *pcFmt, unitptr uHost)

ARGUMENTS

int nu: ABS(nu)=number of successor units to iterate.
int ni: number of iterations
char *pcFmt: option string (see below)
unitptr uHost: host unit

RETURN VALUE:

A pointer to the created unit or NULL in the case of an error.

INTERFACE OF CREATED UNIT:

X_in[1]: index limit. The for_op will iterate its operands for integer index values 0=< i < X_in[0].

out_0[1]: current iteration index; operands are iterated for all integer index values out_0[k] between 0 and X_in[0]-1, inclusive.

DESCRIPTION:

This unit is provided to perform repeated iterations of its nu successor units in the exec-queue. These will become operands of the for_op unit.

EXECUTION:

An exec call to the for_op unit will have the effect to iterate its nu successors over all integer index tuples in the range given by 0..X_in[0](with the latter limit excluded). Changes to the input field of this unit are only noticed before or after the iterations are executed (i.e., changes to the input fields effected by the iterated operands take only effect after the last iteration has been completed). By specifying the %a option (``exec+adapt'' in NEO), the for-iterations will include adaptation steps according to the pattern


   for (i=0; i<steps; i++) {
       exec_unit(Operand_1) ... exec_unit(Operand_nu);
       adapt_unit(Operand_nu) ... adapt_unit(Operand_1);
   }

In this case, no further adaptation calls to the operands will be made during the adapt_unit() call for the for_op.

ADAPTATION:

Usually, the or_op unit does not adapt its operand units. Adaptation must be explicitly enabled by setting options. As explained above, the %a will provide adaptation during the exec_unit call for the for_op unit. The following two options will enable adaptation for the operands of the for_op unit when the adapt_unit call is made.

%A: (``adapt1'' in NEO) adapt_unit() acts as if


   for (i=0; i<ABS(nr); i++) {
       adapt_unit(Operand_nu) ... adapt_unit(Operand_1);
   }

%p: (``adapt2'' in NEO) modifies %A-option by prefixing each adapt_unit(operand) with a exec_unit(operand), ie. now adapt_unit() acts as if


   for (i=0; i<ABS(nr); i++) {
       exec_unit(Operand_nu); adapt_unit(uOperand_nu)
       ...
       exec_unit(Operand_1); adapt_unit(Operand_1)
   }

If the iterated units contain an adaptable unit, each adapt should usually be prefixed by an exec-call, i.e., the %p - mode should be used. If neither of %A or %p is present, the adapt_unit() call is without any effect.

NOTE:

This unit supersedes the older for_loop unit, which should no longer be used for new work.

FILE

/homes/jontrup/nst5/man/../o.sol2//../nstsrc/nst_stdr.c