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$MaxNumber

Status: Stable

documented, exercised by the test suite and/or worked examples, with no known limitations recorded.

Description

$MaxNumber

gives the maximum arbitrary-precision number that can be represented on this computer system.

Notes With USE\_MPFR builds, this is the largest finite value at machine precision under MPFR's current exponent range; otherwise it equals $MaxMachineNumber.

Examples (4)

Every input below was run against the current Mathilda build and its output recorded.

Basic examples (4)

In[1]:= $MachinePrecision
Out[1]= 15.9546

In[2]:= $MachineEpsilon
Out[2]= 2.22045e-16

In[3]:= {$MinMachineNumber, $MaxMachineNumber}
Out[3]= {2.22507e-308, 1.79769e+308}

MPFR, not machine

In[4]:= MachineNumberQ[$MaxNumber]
Out[4]= False

Implementation notes

A Protected OwnValue registered in system_constants_init (src/core.c). In a USE_MPFR build it is the largest finite value at machine precision (DBL_MANT_DIG bits), computed by mpfr_set_inf then mpfr_nextbelow and stored via expr_new_mpfr_move; without MPFR it collapses to expr_new_real(DBL_MAX).

Attributes: Protected.

References

See also: $MachinePrecision, $MachineEpsilon, $MinMachineNumber, $MaxMachineNumber, $MinNumber