Miscellaneous

This page documents the miscellaneous members of the blosc2 module that do not fit into other categories.

blosc2.DEFAULT_COMPLEX

Default complex floating dtype.

Attributes:
T

Scalar attribute identical to the corresponding array attribute.

base

Scalar attribute identical to the corresponding array attribute.

data

Pointer to start of data.

device
dtype

Get array data-descriptor.

flags

The integer value of flags.

flat

A 1-D view of the scalar.

itemset
itemsize

The length of one element in bytes.

nbytes
ndim

The number of array dimensions.

newbyteorder
ptp
shape

Tuple of array dimensions.

size

The number of elements in the gentype.

strides

Tuple of bytes steps in each dimension.

Methods

trace

program/module to trace Python program or function execution

to_device

tobytes
blosc2.DEFAULT_FLOAT

Default real floating dtype.

Attributes:
T

Scalar attribute identical to the corresponding array attribute.

base

Scalar attribute identical to the corresponding array attribute.

data

Pointer to start of data.

device
dtype

Get array data-descriptor.

flags

The integer value of flags.

flat

A 1-D view of the scalar.

itemset
itemsize

The length of one element in bytes.

nbytes
ndim

The number of array dimensions.

newbyteorder
ptp
shape

Tuple of array dimensions.

size

The number of elements in the gentype.

strides

Tuple of bytes steps in each dimension.

Methods

trace

program/module to trace Python program or function execution

to_device

tobytes
blosc2.DEFAULT_INDEX

Default indexing dtype.

Attributes:
T

Scalar attribute identical to the corresponding array attribute.

base

Scalar attribute identical to the corresponding array attribute.

data

Pointer to start of data.

denominator

denominator of value (1)

device
dtype

Get array data-descriptor.

flags

The integer value of flags.

flat

A 1-D view of the scalar.

itemset
itemsize

The length of one element in bytes.

nbytes
ndim

The number of array dimensions.

newbyteorder
numerator

numerator of value (the value itself)

ptp
shape

Tuple of array dimensions.

size

The number of elements in the gentype.

strides

Tuple of bytes steps in each dimension.

Methods

trace

program/module to trace Python program or function execution

to_device

tobytes
blosc2.DEFAULT_INT

Default integer dtype.

Attributes:
T

Scalar attribute identical to the corresponding array attribute.

base

Scalar attribute identical to the corresponding array attribute.

data

Pointer to start of data.

denominator

denominator of value (1)

device
dtype

Get array data-descriptor.

flags

The integer value of flags.

flat

A 1-D view of the scalar.

itemset
itemsize

The length of one element in bytes.

nbytes
ndim

The number of array dimensions.

newbyteorder
numerator

numerator of value (the value itself)

ptp
shape

Tuple of array dimensions.

size

The number of elements in the gentype.

strides

Tuple of bytes steps in each dimension.

Methods

trace

program/module to trace Python program or function execution

to_device

tobytes
class blosc2.Operand[source]

Base class for all operands in expressions.

Attributes:
device

Methods

item()

Copy an element of an array to a standard Python scalar and return it.

to_device
item() → float | bool | complex | int[source]

Copy an element of an array to a standard Python scalar and return it.

class blosc2.ProxyNDField(proxy: Proxy, field: str)[source]
Attributes:
device

Methods

item()

Copy an element of an array to a standard Python scalar and return it.

to_device
class blosc2.finfo(dtype)

Machine limits for floating point types.

bits

The number of bits occupied by the type.

Type:

int

dtype

Returns the dtype for which finfo returns information. For complex input, the returned dtype is the associated float* dtype for its real and complex components.

Type:

dtype

eps

The difference between 1.0 and the next smallest representable float larger than 1.0. For example, for 64-bit binary floats in the IEEE-754 standard, eps = 2**-52, approximately 2.22e-16.

Type:

float

epsneg

The difference between 1.0 and the next smallest representable float less than 1.0. For example, for 64-bit binary floats in the IEEE-754 standard, epsneg = 2**-53, approximately 1.11e-16.

Type:

float

iexp

The number of bits in the exponent portion of the floating point representation.

Type:

int

machep

The exponent that yields eps.

Type:

int

max

The largest representable number.

Type:

floating point number of the appropriate type

maxexp

The smallest positive power of the base (2) that causes overflow.

Type:

int

min

The smallest representable number, typically -max.

Type:

floating point number of the appropriate type

minexp

The most negative power of the base (2) consistent with there being no leading 0’s in the mantissa.

Type:

int

negep

The exponent that yields epsneg.

Type:

int

nexp

The number of bits in the exponent including its sign and bias.

Type:

int

nmant

The number of bits in the mantissa.

Type:

int

precision

The approximate number of decimal digits to which this kind of float is precise.

Type:

int

resolution

The approximate decimal resolution of this type, i.e., 10**-precision.

Type:

floating point number of the appropriate type

tiny

An alias for smallest_normal, kept for backwards compatibility.

Type:

float

smallest_normal

The smallest positive floating point number with 1 as leading bit in the mantissa following IEEE-754 (see Notes).

Type:

float

smallest_subnormal

The smallest positive floating point number with 0 as leading bit in the mantissa following IEEE-754.

Type:

float

Parameters:

dtype (float, dtype, or instance) – Kind of floating point or complex floating point data-type about which to get information.

See also

iinfo

The equivalent for integer data types.

spacing

The distance between a value and the nearest adjacent number

nextafter

The next floating point value after x1 towards x2

Notes

For developers of NumPy: do not instantiate this at the module level. The initial calculation of these parameters is expensive and negatively impacts import times. These objects are cached, so calling finfo() repeatedly inside your functions is not a problem.

Note that smallest_normal is not actually the smallest positive representable value in a NumPy floating point type. As in the IEEE-754 standard [1], NumPy floating point types make use of subnormal numbers to fill the gap between 0 and smallest_normal. However, subnormal numbers may have significantly reduced precision [2].

This function can also be used for complex data types as well. If used, the output will be the same as the corresponding real float type (e.g. numpy.finfo(numpy.csingle) is the same as numpy.finfo(numpy.single)). However, the output is true for the real and imaginary components.

References

[1]

IEEE Standard for Floating-Point Arithmetic, IEEE Std 754-2008, pp.1-70, 2008, https://doi.org/10.1109/IEEESTD.2008.4610935

[2]

Wikipedia, “Denormal Numbers”, https://en.wikipedia.org/wiki/Denormal_number

Examples

>>> import numpy as np
>>> np.finfo(np.float64).dtype
dtype('float64')
>>> np.finfo(np.complex64).dtype
dtype('float32')
Attributes:
smallest_normal

Return the value for the smallest normal.

tiny

Return the value for tiny, alias of smallest_normal.

property smallest_normal

Return the value for the smallest normal.

Returns:

smallest_normal – Value for the smallest normal.

Return type:

float

Warns:

UserWarning – If the calculated value for the smallest normal is requested for double-double.

property tiny

Return the value for tiny, alias of smallest_normal.

Returns:

tiny – Value for the smallest normal, alias of smallest_normal.

Return type:

float

Warns:

UserWarning – If the calculated value for the smallest normal is requested for double-double.

class blosc2.iinfo(type)

Machine limits for integer types.

bits

The number of bits occupied by the type.

Type:

int

dtype

Returns the dtype for which iinfo returns information.

Type:

dtype

min

The smallest integer expressible by the type.

Type:

int

max

The largest integer expressible by the type.

Type:

int

Parameters:

int_type (integer type, dtype, or instance) – The kind of integer data type to get information about.

See also

finfo

The equivalent for floating point data types.

Examples

With types:

>>> import numpy as np
>>> ii16 = np.iinfo(np.int16)
>>> ii16.min
-32768
>>> ii16.max
32767
>>> ii32 = np.iinfo(np.int32)
>>> ii32.min
-2147483648
>>> ii32.max
2147483647

With instances:

>>> ii32 = np.iinfo(np.int32(10))
>>> ii32.min
-2147483648
>>> ii32.max
2147483647