pdf#
- Uniform.pdf(x, /, *, method=None)[source]#
Probability density function
The probability density function (“PDF”), denoted \(f(x)\), is the probability per unit length that the random variable will assume the value \(x\). Mathematically, it can be defined as the derivative of the cumulative distribution function \(F(x)\):
\[f(x) = \frac{d}{dx} F(x)\]pdf
accepts x for \(x\).- Parameters:
- xarray_like
The argument of the PDF.
- method{None, ‘formula’, ‘logexp’}
The strategy used to evaluate the PDF. By default (
None
), the infrastructure chooses between the following options, listed in order of precedence.'formula'
: use a formula for the PDF itself'logexp'
: evaluate the log-PDF and exponentiate
Not all method options are available for all distributions. If the selected method is not available, a
NotImplementedError
will be raised.
- Returns:
- outarray
The PDF evaluated at the argument x.
Notes
Suppose a continuous probability distribution has support \([l, r]\). By definition of the support, the PDF evaluates to its minimum value of \(0\) outside the support; i.e. for \(x < l\) or \(x > r\). The maximum of the PDF may be less than or greater than \(1\); since the valus is a probability density, only its integral over the support must equal \(1\).
References
[1]Probability density function, Wikipedia, https://en.wikipedia.org/wiki/Probability_density_function
Examples
Instantiate a distribution with the desired parameters:
>>> from scipy import stats >>> X = stats.Uniform(a=-1., b=1.)
Evaluate the PDF at the desired argument:
>>> X.pdf(0.25) 0.5