perfplot complains when the `n_range` starts at zero.

[zoj613]

if n_range=[i for i in range(100)], I get the following

/home/lib/python3.8/site-packages/perfplot/main.py:78: RuntimeWarning: divide by zero encountered in log
  log_n_range = numpy.log(self.n_range)
/home/lib/python3.8/site-packages/numpy/core/function_base.py:144: RuntimeWarning: invalid value encountered in multiply
  y *= step
/home/lib/python3.8/site-packages/numpy/core/function_base.py:154: RuntimeWarning: invalid value encountered in add
  y += start
/home/lib/python3.8/site-packages/perfplot/main.py:78: RuntimeWarning: divide by zero encountered in log
  log_n_range = numpy.log(self.n_range)
/home/python3.8/site-packages/numpy/core/function_base.py:144: RuntimeWarning: invalid value encountered in multiply
  y *= step
/home/lib/python3.8/site-packages/numpy/core/function_base.py:154: RuntimeWarning: invalid value encountered in add
  y += start

which caused by taking log of zero.

[nschloe]

As always, a full MWE is required to reproduce.

[zoj613]

As always, a full MWE is required to reproduce.

You're right. An example that reproduces this is the one in the README but using bench instead of plot.

import perfplot
import numpy

out = perfplot.bench(
    setup=lambda n: numpy.random.rand(n),  # or setup=numpy.random.rand
    kernels=[
        lambda a: numpy.c_[a, a],
        lambda a: numpy.stack([a, a]).T,
        lambda a: numpy.vstack([a, a]).T,
        lambda a: numpy.column_stack([a, a]),
        lambda a: numpy.concatenate([a[:, None], a[:, None]], axis=1),
    ],
    labels=["c_", "stack", "vstack", "column_stack", "concat"],
    n_range=[k for k in range(5)],
    xlabel="len(a)",
)
out.show()

output:

/home/lib/python3.8/site-packages/perfplot/main.py:78: RuntimeWarning: divide by zero encountered in log
  log_n_range = numpy.log(self.n_range)
/home/a/lib/python3.8/site-packages/numpy/core/function_base.py:144: RuntimeWarning: invalid value encountered in multiply
  y *= step
/home/lib/python3.8/site-packages/numpy/core/function_base.py:154: RuntimeWarning: invalid value encountered in add
  y += start

It seems to me the default behavior is to log the output, which gives problems when n_range is required to start at 0. Using logx=False and logy=False in show() silences the warnings but this behavior is weird and confusing. Maybe the user should explicitly set scaling to log when required, not by default?

[zoj613]

thanks @nschloe