log_scale

Context: axes

Synopsis

Changes the plot axis to use a logarithmic scale.

Syntax

log_scale([plotname,] [dimension])
log_scale([ChipsId,] [dimension])

The function is also available as logarithmic_scale().

Description

plotname - an optional string giving the name of the plot in the current frame to modify.
ChipsId - an optional ChipsId structure containing values to modify the currency state for the command.
dimension - operate on axis in X dimension (X_AXIS), Y dimension (Y_AXIS), or both (XY_AXIS). If no dimension is specified, the command is applied to both axes.

The log_scale command changes the given axis (or axes) to use a logarithmic scale. To change back to a linear scale use the lin_scale command.

When the scale of an axis is changed, any axes that are bound to that axis are also changed, including plot border axes; see "ahelp bind_axes" for more information.

How negative values are handled

If the lower limit of an axis is 0 or less, then the lower limit will be re-calculated from the smallest positive value in the associated data set(s) for that axis. This happens whether the axis limit is "AUTO" or has been set to a specific value.

If both limits are 0 or less then the call will succeed but the axis will display no data or tick marks.

Example 1

chips> log_scale()

Set the current X and Y axis to log scale.

Example 2

chips> log_scale(X_AXIS)

Set the current X axis to log scale.

Example 3

chips> log_scale("plot1")

These commands change the X and Y axes of the plot called "plot1" to a logarithmic scale. For this example the output of the "info" command is:

Window [win1]
  Frame [frm1]
    Plot [plot1]   (0.15,0.52)  .. (0.90,0.90)
      Border bottom [bx1]  top [bx2]  left [by1]  right [by2]
      X Axis [ax1]
      Y Axis [ay1]
      Curve [crv1]
    Plot [plot2]   (0.15,0.15)  .. (0.90,0.52)
      Border bottom [bx1]  top [bx2]  left [by1]  right [by2]
      X Axis [ax1]
      Y Axis [ay1]
      Curve [crv1]

Example 4

chips> id = ChipsId()
chips> id.plot = "plot1"
chips> log_scale(id)

An alternative means to change the scaling of the axes in plot "plot1". This method is the only way to directly change a plot that is not in the current frame: for example

chips> id.window = "win2"
chips> id.plot = "plot2"
chips> log_scale(id, Y_AXIS)

will change the Y axis of the plot called "plot2" in window "win2" to be drawn with a logarithmic scale.

Bugs

See the bugs pages on the ChIPS website for an up-to-date listing of known bugs.