Error using cppelt - findchangepts function

Hello everyone,

I need to get the breakpoints of a time series. I coded

bp = findchangepts(data,'MaxNumChanges',2);

However I obtained

Error using cppelt

The input data type must be either single or double precision

Error in findchangepts>cpmulti (line 241)

[cpmax, minresidue] = cppelt(x, 0, Lmin, statistic);

Error in findchangepts (line 76)

[cp, residue] = cpmulti(x, statistic, Lmin, Kmax);

Apparently, the problem is 'MaxNumChanges',2, because if I skip it, I get a result (only 1 breakpoint). My data type is double precision, so I don't understand what happens

Somebody could help me, please?

Thanks a lot

Answer 1

[Star Strider]

Your findchangepts call works correctly when I test it here —

t = linspace(0, 10);
data = +(t>4.5);                                                % The '+' Converts 'logical' To 'double'

bp = findchangepts(data,'MaxNumChanges',2)

bp = 46

figure
plot(t, data, t(bp), data(bp), 'pg', 'MarkerSize',11)
grid
ylim([-0.1 1.1])

whos t data

  Name      Size             Bytes  Class     Attributes

  data      1x100              800  double              
  t         1x100              800  double              

Use whos to be certain that your data are single or double as findchangepts requires.

.