pymc.exceptions.SamplingError for three normal variables the means whereof are 0 and the standard deviations whereof have independent logarithmic priors

Questions v5
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4

Is the best way to specify a logarithmic prior in PyMC the following?

import pymc as pm

pm.CustomDist(
    "std",
    logp=lambda tensor: -pm.math.log(tensor),
    transform=pm.distributions.transforms.log,
    initval=1.0,
)