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Function Reference: hnpdf

statistics: y = hnpdf (x, mu, sigma)

Half-normal probability density function (PDF).

For each element of x, compute the probability density function (PDF) of the half-normal distribution with location parameter mu and scale parameter sigma. The size of y is the common size of x, mu, and sigma. A scalar input functions as a constant matrix of the same size as the other inputs.

The half-normal CDF is only defined for x >= mu.

Further information about the half-normal distribution can be found at https://en.wikipedia.org/wiki/Half-normal_distribution

See also: hncdf, hninv, hnrnd, hnfit, hnlike, hnstat

Source Code: hnpdf

Example: 1

Plot various PDFs from the half-normal distribution

 x = 0:0.001:10;
 y1 = hnpdf (x, 0, 1);
 y2 = hnpdf (x, 0, 2);
 y3 = hnpdf (x, 0, 3);
 y4 = hnpdf (x, 0, 5);
 plot (x, y1, '-b', x, y2, '-g', x, y3, '-r', x, y4, '-c')
 grid on
 xlim ([0, 10])
 ylim ([0, 0.9])
 legend ({'μ = 0, σ = 1', 'μ = 0, σ = 2', ...
          'μ = 0, σ = 3', 'μ = 0, σ = 5'}, 'location', 'northeast')
 title ('Half-normal PDF')
 xlabel ('values in x')
 ylabel ('density')
plotted figure

Example: 2

Plot half-normal against normal probability density function

 x = -5:0.001:5;
 y1 = hnpdf (x, 0, 1);
 y2 = normpdf (x);
 plot (x, y1, '-b', x, y2, '-g')
 grid on
 xlim ([-5, 5])
 ylim ([0, 0.9])
 legend ({'half-normal with μ = 0, σ = 1', ...
          'standard normal (μ = 0, σ = 1)'}, 'location', 'northeast')
 title ('Half-normal against standard normal PDF')
 xlabel ('values in x')
 ylabel ('density')
plotted figure