hist
==============================================

Purpose
----------------

Computes and graphs a frequency histogram for a vector. The actual frequencies are plotted for each category.

.. NOTE:: this function is for use with the deprecated PQG graphics. Use :func:`plotHist` instead.

Library
-------

pgraph

Format
----------------
.. function:: { b, m, freq } = hist(x, v)

    :param x: data
    :type x: Mx1 vector

    :param v: the breakpoints to be used to compute the frequencies (vector) -or- the number of categories (scalar).
    :type v: Nx1 vector or scalar

    :return b: the breakpoints used for each category.

    :rtype b: Px1 vector

    :return m: the midpoints of each category.

    :rtype m: Px1 vector

    :return freq: computed frequency counts.

    :rtype freq: Px1 vector

Examples
----------------

::

    library pgraph;
    x = rndn(5000,1);
    { b, m, f } = hist(x, 20);

Remarks
-------

If a vector of breakpoints is specified, a final breakpoint equal to the
maximum value of *x* will be added if the maximum breakpoint value is
smaller.

If a number of categories is specified, the data will be divided into *v*
evenly spaced categories.

Each time an element falls into one of the categories specified in *b*,
the corresponding element of freq will be incremented by one. The
categories are interpreted as follows:

::

   freq[1] =          x < b[1]
   freq[2] = b[1]   < x < b[2]
   freq[3] = b[2]   < x < b[3]
     .
     .
     .
   freq[P] = b[P-1] < x < b[P]


Source
------

phist.src

.. seealso:: Functions :func:`histp`, :func:`histf`, :func:`bar`