Change sign of descending values

How can i change the sign of decending values ?

4165

4230

4296

4361

4430

4476

4549

4604

4664

4705

4710

4714

4718

4718

4716

4713

4708

4697

4646

4572

4491

[James Tursa]

What is the exact desired output for your example?

Answer 1

[James Tursa]

Is this what you want?

x = your vector of values
d = [1;diff(x)];
x(d<0) = -x(d<0);