Normalizer with corresponding parameters doesn't work?

[munechika-koyo]

Summary

Plotting 2D images with the norm parameter and corresponding value limits like vmin, vmax, etc. doesn't work well.

Reproducer

Preamble is

import numpy as np
import ultraplot as uplt

N = 20
state = np.random.RandomState(51423)
data = 11 ** (0.25 * np.cumsum(state.rand(N, N), axis=0))

fig, ax = uplt.subplots()

When specifing vmin like:

ax.pcolormesh(data, cmap="magma", norm="log", vmin=1e-2)

then, we see the following error:

ValueError Traceback (most recent call last)
Cell In[110], line 6
 2 state = np.random.RandomState(51423)
 3 data = 11 ** (0.25 * np.cumsum(state.rand(N, N), axis=0))
 4 fig, ax = uplt.subplots()
----> 5 ax.pcolormesh(data, cmap="magma", norm="log", vmin=1e-2)

File ~/Documents/cherab/iter/.pixi/envs/default/lib/python3.14/site-packages/ultraplot/internals/inputs.py:405, in _preprocess_or_redirect.<locals>._decorator.<locals>._preprocess_or_redirect(self, *args, **kwargs)
 403 kwargs["color"] = color
 404 # Call main function
--> 405 return func(self, *args, **kwargs)

File ~/Documents/cherab/iter/.pixi/envs/default/lib/python3.14/site-packages/ultraplot/axes/plot.py:7280, in PlotAxes.pcolormesh(self, x, y, z, **kwargs)
 7278 kw.update(_pop_props(kw, "collection"))
 7279 center_levels = kw.pop("center_levels", None)
-> 7280 kw = self._parse_cmap(
 7281 x, y, z, to_centers=to_centers, center_levels=center_levels, **kw
 7282 )
 7283 edgefix_kw = _pop_params(kw, self._fix_patch_edges)
 7284 labels_kw = _pop_params(kw, self._add_auto_labels)

File ~/Documents/cherab/iter/.pixi/envs/default/lib/python3.14/site-packages/ultraplot/internals/warnings.py:119, in _rename_kwargs.<locals>._decorator.<locals>._deprecate_kwargs_wrapper(*args, **kwargs)
 114 key_new = key_new.format(value)
 115 _warn_ultraplot(
 116 f"Keyword {key_old!r} was deprecated in version {version} and may "
 117 f"be removed in {next_release()}. Please use {key_new!r} instead."
 118 )
--> 119 return func_orig(*args, **kwargs)

File ~/Documents/cherab/iter/.pixi/envs/default/lib/python3.14/site-packages/ultraplot/axes/plot.py:4125, in PlotAxes._parse_cmap(self, cmap, cmap_kw, c, color, colors, norm, norm_kw, extend, vmin, vmax, discrete, default_cmap, default_discrete, skip_autolev, min_levels, plot_lines, plot_contours, center_levels, *args, **kwargs)
 4123 # If norm is given we use it to set vmin and vmax
 4124 if (vmin is not None or vmax is not None) and norm is not None:
-> 4125 raise ValueError("If 'norm' is given, 'vmin' and 'vmax' must not be set.")
 4126 if isinstance(norm, mcolors.Normalize):
 4127 vmin = norm.vmin

ValueError: If 'norm' is given, 'vmin' and 'vmax' must not be set.

Another case like:

ax.pcolormesh(data, cmap="magma", norm=("log", 1e-2))

shows the following error:

TypeError Traceback (most recent call last)
Cell In[111], line 5
 1 N = 20
 2 state = np.random.RandomState(51423)
 3 data = 11 ** (0.25 * np.cumsum(state.rand(N, N), axis=0))
 4 fig, ax = uplt.subplots()
----> 5 ax.pcolormesh(data, cmap="magma", norm=("log", 1e-2))

File ~/Documents/cherab/iter/.pixi/envs/default/lib/python3.14/site-packages/ultraplot/internals/inputs.py:405, in _preprocess_or_redirect.<locals>._decorator.<locals>._preprocess_or_redirect(self, *args, **kwargs)
 403 kwargs["color"] = color
 404 # Call main function
--> 405 return func(self, *args, **kwargs)

File ~/Documents/cherab/iter/.pixi/envs/default/lib/python3.14/site-packages/ultraplot/axes/plot.py:7280, in PlotAxes.pcolormesh(self, x, y, z, **kwargs)
 7278 kw.update(_pop_props(kw, "collection"))
 7279 center_levels = kw.pop("center_levels", None)
-> 7280 kw = self._parse_cmap(
 7281 x, y, z, to_centers=to_centers, center_levels=center_levels, **kw
 7282 )
 7283 edgefix_kw = _pop_params(kw, self._fix_patch_edges)
 7284 labels_kw = _pop_params(kw, self._add_auto_labels)

File ~/Documents/cherab/iter/.pixi/envs/default/lib/python3.14/site-packages/ultraplot/internals/warnings.py:119, in _rename_kwargs.<locals>._decorator.<locals>._deprecate_kwargs_wrapper(*args, **kwargs)
 114 key_new = key_new.format(value)
 115 _warn_ultraplot(
 116 f"Keyword {key_old!r} was deprecated in version {version} and may "
 117 f"be removed in {next_release()}. Please use {key_new!r} instead."
 118 )
--> 119 return func_orig(*args, **kwargs)

File ~/Documents/cherab/iter/.pixi/envs/default/lib/python3.14/site-packages/ultraplot/axes/plot.py:4249, in PlotAxes._parse_cmap(self, cmap, cmap_kw, c, color, colors, norm, norm_kw, extend, vmin, vmax, discrete, default_cmap, default_discrete, skip_autolev, min_levels, plot_lines, plot_contours, center_levels, *args, **kwargs)
 4247 norm.vmin, norm.vmax = vmin, vmax
 4248 else:
-> 4249 norm = constructor.Norm(norm, vmin=vmin, vmax=vmax, **norm_kw)
 4250 isdiverging = autodiverging and isinstance(norm, pcolors.DivergingNorm)
 4251 if not trues and isdiverging and modes["diverging"] is None:

File ~/Documents/cherab/iter/.pixi/envs/default/lib/python3.14/site-packages/ultraplot/constructor.py:1101, in Norm(norm, *args, **kwargs)
 1099 if norm == "symlog" and not args and "linthresh" not in kwargs:
 1100 kwargs["linthresh"] = 1 # special case, needs argument
-> 1101 return NORMS[norm](*args, **kwargs)

File ~/Documents/cherab/iter/.pixi/envs/default/lib/python3.14/site-packages/matplotlib/colors.py:2651, in _make_norm_from_scale.<locals>.Norm.__init__(self, *args, **kwargs)
 2650 def __init__(self, *args, **kwargs):
-> 2651 ba = bound_init_signature.bind(*args, **kwargs)
 2652 ba.apply_defaults()
 2653 super().__init__(
 2654 **{k: ba.arguments.pop(k) for k in ["vmin", "vmax", "clip"]})

File ~/Documents/cherab/iter/.pixi/envs/default/lib/python3.14/inspect.py:3236, in Signature.bind(self, *args, **kwargs)
 3231 def bind(self, /, *args, **kwargs):
 3232 """Get a BoundArguments object, that maps the passed `args`
 3233 and `kwargs` to the function's signature. Raises `TypeError`
 3234 if the passed arguments can not be bound.
 3235 """
-> 3236 return self._bind(args, kwargs)

File ~/Documents/cherab/iter/.pixi/envs/default/lib/python3.14/inspect.py:3173, in Signature._bind(self, args, kwargs, partial)
 3170 break
 3172 if param.name in kwargs and param.kind != _POSITIONAL_ONLY:
-> 3173 raise TypeError(
 3174 'multiple values for argument {arg!r}'.format(
 3175 arg=param.name)) from None
 3177 arguments[param.name] = arg_val
 3179 # Now, we iterate through the remaining parameters to process
 3180 # keyword arguments

TypeError: multiple values for argument 'vmin'

Is this a bug, or did I mistakenly set it up?

[cvanelteren]

The last case is something that is not possible I think. The others are parsing errors on our end.

[cvanelteren]

Will have a look later today.

[munechika-koyo]

Thank you for taking it into account.
According to the documentation about norm, it seems that the norm argument can take a tuple value, the elements of which, starting from the second one, are interpreted as arguments for the normalizer constructor.
So, is it reasonable to assume that norm=("log", 0.1) is the same as norm=LogNorm(0.1)?

[cvanelteren]

You are right! Missed it in the docs. I fixed it on #693