# CausalVariant

Source: https://www.tensorplay.cn/docs/generated/tensorplay.nn.attention.bias.CausalVariant.html

```python
class tensorplay.nn.attention.bias.CausalVariant(*values)
```

Enum for causal variants used in attention mechanisms.

Defines two types of causal biases:

UPPER_LEFT: Represents upper-left triangular bias for standard causal attention.
The equivalent code for constructing this bias is:

```
tensorplay.tril(tensorplay.ones(size, dtype=tensorplay.bool))
```

For instance, with shape=(3,4), the materialized bias tensor will be:

```
[[1, 0, 0, 0],
 [1, 1, 0, 0],
 [1, 1, 1, 0]]
```

LOWER_RIGHT: Represents lower-right triangular bias, the include values are aligned to the lower
right corner of the matrix.

The equivalent code for constructing this bias is:

```
diagonal_offset = size[1] - size[0]
tensorplay.tril(
    tensorplay.ones(size, dtype=tensorplay.bool),
    diagonal=diagonal_offset,
)
```

For instance, with shape=(3,4), the materialized bias tensor will be:

```
[[1, 1, 0, 0],
 [1, 1, 1, 0],
 [1, 1, 1, 1]]
```

Note that these variants are equivalent to each other when the sequence lengths of the query and key/value
tensors are equal since the triangular matrix is square.

> **Warning**
>
> This enum is a prototype and subject to change.

```python
as_integer_ratio()
```

Return a pair of integers, whose ratio is equal to the original int.

The ratio is in lowest terms and has a positive denominator.

```
>>> (10).as_integer_ratio()
(10, 1)
>>> (-10).as_integer_ratio()
(-10, 1)
>>> (0).as_integer_ratio()
(0, 1)
```

```python
bit_count()
```

Number of ones in the binary representation of the absolute value of self.

Also known as the population count.

```
>>> bin(13)
'0b1101'
>>> (13).bit_count()
3
```

```python
bit_length()
```

Number of bits necessary to represent self in binary.

```
>>> bin(37)
'0b100101'
>>> (37).bit_length()
6
```

```python
conjugate()
```

Returns self, the complex conjugate of any int.

```python
denominator
```

the denominator of a rational number in lowest terms

```python
classmethod from_bytes(bytes, byteorder='big', *, signed=False)
```

```python
imag
```

the imaginary part of a complex number

```python
is_integer()
```

Returns True. Exists for duck type compatibility with float.is_integer.

```python
numerator
```

the numerator of a rational number in lowest terms

```python
real
```

the real part of a complex number

```python
to_bytes(length=1, byteorder='big', *, signed=False)
```