fixpt_evenspace_cleanup - Modify breakpoints of lookup table to have even spacing
Syntax
xdata_modified = fixpt_evenspace_cleanup(xdata,xdt,xscale)
Description
xdata_modified = fixpt_evenspace_cleanup(xdata,xdt,xscale) modifies
breakpoints of a lookup table to have even spacing after quantization.
By adjusting breakpoints to have even spacing after quantization, Real-Time Workshop generated
code can exclude breakpoints from memory.
xdata is the breakpoint vector of
a lookup table to make evenly spaced, such as 0:0.005:1. xdt is
the data type of the breakpoints, such as sfix(16). xscale is
the scaling of the breakpoints, such as 2^-12.
Using these three inputs, fixpt_evenspace_cleanup returns
the modified breakpoints in xdata_modified.
This function works only with nontunable data and considers
data to have even spacing relative to the scaling slope. For example,
the breakpoint vector [0 2 5], which has spacing value 2 and 3, appears
to have uneven spacing. However, the difference between the maximum
spacing 3 and the minimum spacing 2 equals 1. If the scaling slope
is 1 or greater, a spacing variation of 1 represents a 1-bit change
or less. In this case, the fixpt_evenspace_cleanup function
considers a spacing variation of 1 bit or less to be even.
Modifications to breakpoints can change the numerical behavior
of a lookup table. To check for changes, test the model using simulation,
rapid prototyping, or other appropriate methods.
Examples
Modify breakpoints of a lookup table to have even spacing after
quantization:
xdata = 0:0.005:1;
xdt = sfix(16);
xscale = 2^-12;
xdata_modified = fixpt_evenspace_cleanup(xdata,xdt,xscale)
See Also
fixdt | fixpt_interp1 | fixpt_look1_func_approx | fixpt_look1_func_plot | sfix | ufix
 | fixdt | | fixpt_interp1 |  |
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