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App version: 3.4.12

Histograms in Neptune

To track activations or other distributions across steps, you can log a series of histograms to a Neptune run.

Log histogram series​

To log a histogram series:

  1. Define the histogram with the Histogram Neptune type.
  2. To log the histogram to a specific step, pass the histogram to the log_histograms() function.

Defining a histogram​

Import Histogram from the Neptune types:

from neptune_scale.types import Histogram

You can specify a histogram with NumPy:

import numpy as np


a = np.arange(5)
Counts
counts, bin_edges = np.histogram(a, density=False)
neptune_histogram = Histogram(bin_edges=bin_edges, counts=counts)
Densities
densities, bin_edges = np.histogram(a, density=True)
neptune_histogram = Histogram(bin_edges=bin_edges, densities=densities)

You can also use another framework, or pass custom values:

my_histogram = Histogram(
    bin_edges=[0, 1, 40, 89, 1000],
    counts=[5, 82, 44, 1],
)

If using densities, they should represent probability density function values per bin. This way, the area of the histogram bars will be equal to 1.

my_histogram = Histogram(
    bin_edges=[0, 1, 2, 3, 4],
    densities=[0.25, 0.25, 0.25, 0.25],
)

Bin edges​

When specifying the bin edges, the left edge is inclusive and the right exclusive.

For example, the bin edges [0, 1, 40] result in the intervals [0, 1) and [1, 40).

note

Infinity values aren't supported as bin edges.

Logging a histogram per step​

You can log one or more histogram series at a particular step in a single function call:

Log a single histogram series per step
from neptune_scale import Run
from neptune_scale.types import Histogram


run = Run(...)

for step in epoch:
    # your training loop

    my_histogram = Histogram(...)

    run.log_histograms(
        histograms={
            "layers/1/activations": my_histogram
        },
        step=step,
    )
Log multiple histogram series per step
for step in epoch:
    # your training loop

    my_histogram_1 = Histogram(...)
    my_histogram_2 = Histogram(...)
    my_histogram_3 = Histogram(...)

    run.log_histograms(
        histograms={
            "layers/1/activations": my_histogram_1,
            "layers/2/activations": my_histogram_2,
            "layers/3/activations": my_histogram_3,
        },
        step=step,
    )

View histograms in the app​

In the Neptune web app, you can visualize the logged histograms in a dashboard or report.

The distribution at each step is plotted as a vertical stack of bars:

Histogram widget displaying distributions per step.

Each color corresponds to a run, and the color intensity indicates the sample count or density.

When you hover over the widget area, the tooltip shows the detailed distributions as regular histograms. The dotted line indicates the cursor position: The vertical line in the tooltip corresponds to the horizontal line in the widget area.

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