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Update

Catalog of update functions.

AbstractUpdate

Bases: Module

Ensures that all update functions have the same signatures.

Source code in src/somap/update.py 
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class AbstractUpdate(eqx.Module):
    """Ensures that all update functions have the same signatures."""

    @abstractmethod
    def __call__(self, lr, nbh, input_bu, w_bu):
        """SOM Update function.

        Args:
            lr: Learning rate.
            nbh: Neighborhood.
            input_bu: Data input.
            w_bu: Prototype weights.

        Returns:
            The updated prototype weights.
        """
        pass

__call__(lr, nbh, input_bu, w_bu) abstractmethod

SOM Update function.

Parameters:

Name Type Description Default
lr

Learning rate.

 required
nbh

Neighborhood.

 required
input_bu

Data input.

 required
w_bu

Prototype weights.

 required

Returns:

Type Description

The updated prototype weights.
Source code in src/somap/update.py 
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@abstractmethod
def __call__(self, lr, nbh, input_bu, w_bu):
    """SOM Update function.

    Args:
        lr: Learning rate.
        nbh: Neighborhood.
        input_bu: Data input.
        w_bu: Prototype weights.

    Returns:
        The updated prototype weights.
    """
    pass

CyclicSomUpdate

Bases: AbstractUpdate

Cyclic update functions.

Source code in src/somap/update.py 
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@experimental_warning
class CyclicSomUpdate(AbstractUpdate):
    """Cyclic update functions."""

    def __call__(self, lr, nbh, input_bu, w_bu):
        """Updates the prototype weights where 0 is the same as 1."""
        # convert [0:1] float range into [0:255] integer range
        input_bu_uint8 = (input_bu * 255).astype(jnp.uint8)
        w_bu_uint8 = (w_bu * 255).astype(jnp.uint8)

        # interpret the diff as an unsigned int8
        # diff is between -1 and 1
        diff = (input_bu_uint8 - w_bu_uint8).astype(jnp.int8) / 128.0

        # out may escape the [0:1] interval, so it needs a modulo 1
        out = (lr * nbh)[:, :, jnp.newaxis] * diff + w_bu
        out = out % 1

        return out

__call__(lr, nbh, input_bu, w_bu)

Updates the prototype weights where 0 is the same as 1.

Source code in src/somap/update.py 
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def __call__(self, lr, nbh, input_bu, w_bu):
    """Updates the prototype weights where 0 is the same as 1."""
    # convert [0:1] float range into [0:255] integer range
    input_bu_uint8 = (input_bu * 255).astype(jnp.uint8)
    w_bu_uint8 = (w_bu * 255).astype(jnp.uint8)

    # interpret the diff as an unsigned int8
    # diff is between -1 and 1
    diff = (input_bu_uint8 - w_bu_uint8).astype(jnp.int8) / 128.0

    # out may escape the [0:1] interval, so it needs a modulo 1
    out = (lr * nbh)[:, :, jnp.newaxis] * diff + w_bu
    out = out % 1

    return out

SomUpdate

Bases: AbstractUpdate

Generic update function.

Source code in src/somap/update.py 
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class SomUpdate(AbstractUpdate):
    """Generic update function."""

    def __call__(
        self,
        lr: Float[Array, "..."],
        nbh: Float[Array, "..."],
        input_bu: Float[Array, "..."],
        w_bu: Float[Array, "..."],
    ) -> Float[Array, "..."]:
        """Updates the prototype weights."""
        out = w_bu + (lr * nbh)[:, :, jnp.newaxis] * (input_bu - w_bu)
        return jnp.clip(out, 0, 1.0)

__call__(lr, nbh, input_bu, w_bu)

Updates the prototype weights.

Source code in src/somap/update.py 
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def __call__(
    self,
    lr: Float[Array, "..."],
    nbh: Float[Array, "..."],
    input_bu: Float[Array, "..."],
    w_bu: Float[Array, "..."],
) -> Float[Array, "..."]:
    """Updates the prototype weights."""
    out = w_bu + (lr * nbh)[:, :, jnp.newaxis] * (input_bu - w_bu)
    return jnp.clip(out, 0, 1.0)