INF, NAN, and Null

These are special values that Analytica returns in particular conditions. You can also use them in expressions:

Inf means infinity -- e.g.,

1/0 → Inf

or a number larger than 1.796E308 (due to computer limitations) -- e.g.

1E307 * 100 → Inf

-Inf means negative infinity -- e.g.,

-1/0 → -Inf

or a number less than 1.796E308

NAN means "Not A Number", where the result is numeric, but not a real number or infinity -- e.g.

0/0 → NAN

Sqrt(-1) → NAN

except if you enable Complex numbers, in which case this will return a valid imaginary number, 1j.

Null means that there is no such value. For example, Slice, Subscript, SubIndex, or MdTable return if you try to Slice out the nth slice over an Index with less than n values.

More on INF and NAN

Analytica follows ANSI (Association of National Standards Institutes) standards for computing with these special values, where applicable.

1/Inf → 0

1/(-Inf) → 0

Inf + Inf → Inf

Inf - Inf → NAN

More on NULL

When NULL appears in scalar operations, it generally produces a warning and evaluates to NULL, for example:

10 + NULL → NULL

NULL - 10 → NULL

1 AND NULL → NULL

Array-reducing functions ignore NULL. These examples demonstrate (assume A is indexed by I as indicated).

I:	1	2	3	4	5
A:	8	NULL	4	NULL	0

Sum(A, I) → 12

Average(A, I) → 4

JoinText(A, I, ', ') → "8, 4, 0"

Graphs will simply ignore (not show) any point whose value is NULL.

Array-reducing functions include Sum, Min, Max, ArgMin, ArgMax, Product, Average, JoinText, Irr, Npv. Array functions Sum, Min and Max also accept an optional parameter IgnoreNaN to ignore NaN values (which otherwise propagate, i.e. return NaN).

Regression also ignores any data points which have Y=Null, which is useful for missing data.