yMax

Ymax is a term used to denote the maximum value of the y-coordinate in a dataset, graph, or plotting range. It does not refer to a universal constant; its value depends on the context, including the data being analyzed or the function being plotted. In Cartesian coordinates, a point has coordinates (x, y). Ymax may refer to the greatest y among a set of points, or to the maximum value of a function over a specified domain, thereby indicating the vertical extent or amplitude of a graph.

In data visualization and plotting software, ymax is commonly used as a parameter to specify the upper limit of the y-axis. Setting an appropriate ymax helps enhance readability by keeping all relevant data visible while leaving room for labels and variations. Different systems name and apply this limit in varying ways: for example, some libraries allow an axis range specified as [ymin, ymax], while others provide dedicated properties or functions to set the top bound of the axis. In Python's matplotlib, for instance, the y-axis upper limit can be controlled via ylim(top=ymax) or by setting the upper value in set_ylim. Other environments like MATLAB or GNUPlot use similar concepts with their own syntax.

Computationally, ymax is often obtained as ymax = max(y) for a list or array y. It may then be used for normalization, clipping, or as a safeguard in plotting routines to prevent the axis from truncating important values. See also y-axis, maximum, and max function.