DPlot

Dear forum,

my name is Boris and I am new to DPlot but very impressed with the ease of use.

There is one task that I would like to do in Dplot and perhaps it is possible,

I have data such like
(x,y)
(1,10)
(2,20)
(3,20)
(4,25)
(5,32)

and would like to produce a sequence where each point in Y is the difference between Y(n)-Y(n-1) - this would make the first point invalid.

(.,.)
(2,10) -- 20-10
(3,0) -- 20-20
(4,5) -- 25 -20
(5,7) -- 32 - 25

Can this be done ?

The file is large so I cannot do it in Excel.

best regards,

B.

p.s.

Just figured, since x increments by 1, I can differentiate the curve

I will try that once I have the data set here.

B.

The Differentiate command in the current version will not do what you want (or at least not what you described). (The next release will, because it includes a "Previous point" method that uses Y(n) and Y(n-1), as opposed to the "Central difference" method, which uses Y(n+1) and Y(n-1)).

You can do this: Use Edit>Copy>Data values and Edit>Paste to add a copy of your original data. Use Edit>Operate on X with X=X+1 on the copy. This shifts all points in the copy to the right by 1. Then use Generate>Y=f(X,Y1,Y2,...) with Y=Y2-Y1.

Many thanks,

That should do what I need - excellent. I had not thought of that combination of moves, that is very flexible.

Thank you !

B.