algebra: OPTIONS

SYNTAX-CHECK

New instructions entered via INSERT are checked by default (ALGEBRA-SYNTAX-CHECK) on correct syntax as part of a sequential algebra instruction list, which can in principle be executed entirely within the ALGEXn routines.

The instruction codes for return, goto, argument and call are processed at a higher level. Such instruction codes are used for instance when addressing elements of matrices. These codes are accepted only if you have set PROCEDURE-SYNTAX-CHECK.

You may change also switch syntax checking off altogether.

IGNORE-EXPONENTIAL-UNDERFLOW

If the SIGNAL-EXPONENTIAL-UNDERFLOW option is in effect, which is the initial setting, exponentials of negative numbers less than -40 are signalled as underflows. Formulae in which they occur are not evaluated.

To have such exponentials set to 0 and to continue evaluating the formula, the IGNORE-EXPONENTIAL-UNDERFLOW option is used. When IGNORE-EXPONENTIAL-UNDERFLOW is in effect, underflows are not counted.

Note that this option applies only to exponentials evaluated by algebraic expressions, not to exponentials computed by regular Garfield commands.

These options may also be written IGNORE-UNDERFLOW and SIGNAL-UNDERFLOW.

[By default, exponential underflows are not signalled.]

IGNORE-INPUT-UNDERFLOW

Values part of commands that are smaller in absolute value than 10\<SUP\>-30\</SUP\> are by default set equal to 0.

This does not apply to results of calculations, for which other limits apply, as explained for the IGNORE-EXPONENTIAL-UNDERFLOW option.

[By default, underflow on input is ignored.]

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Formatted on 21/01/18 at 16:55.