Type Info

Created On: Jun 06, 2025 | Last Updated On: Aug 14, 2025

The numerical properties of a torch.dtype can be accessed through either the torch.finfo or the torch.iinfo.

torch.finfo

class torch.finfo

A torch.finfo is an object that represents the numerical properties of a floating point torch.dtype, (i.e. torch.float32, torch.float64, torch.float16, and torch.bfloat16). This is similar to numpy.finfo.

A torch.finfo provides the following attributes:

Name	Type	Description
bits	int	The number of bits occupied by the type.
eps	float	The difference between 1.0 and the next smallest representable float larger than 1.0.
max	float	The largest representable number.
min	float	The smallest representable number (typically -max).
tiny	float	The smallest positive normal number. Equivalent to smallest_normal.
smallest_normal	float	The smallest positive normal number. See notes.
resolution	float	The approximate decimal resolution of this type, i.e., 10**-precision.

Note

The constructor of torch.finfo can be called without argument, in which case the class is created for the pytorch default dtype (as returned by torch.get_default_dtype()).

Note

smallest_normal returns the smallest normal number, but there are smaller subnormal numbers. See https://en.wikipedia.org/wiki/Denormal_number for more information.

torch.iinfo

class torch.iinfo

A torch.iinfo is an object that represents the numerical properties of a integer torch.dtype (i.e. torch.uint8, torch.int8, torch.int16, torch.int32, and torch.int64). This is similar to numpy.iinfo.

A torch.iinfo provides the following attributes:

Name	Type	Description
bits	int	The number of bits occupied by the type.
max	int	The largest representable number.
min	int	The smallest representable number.