error code on cumsum

I am attempting to run: A = 1 - cumsum(C)/sum(C); where C is a long column vector. I receive error "??? Error using ==> cumsum CUMSUM is not supported for integer input." What does it mean?

[per isakson]

The code looks ok. Make this check

    which cumsum -all

what does it say? And what does

    class( C )

say? And which Matlab release do you use?

[Ralph]

response to 'which cumsum -all' EDU>> which cumsum -all built-in (C:\Program Files (x86)\MATLAB\R2010a Student\toolbox\matlab\datafun\@single\cumsum) % single method

built-in (C:\Program Files (x86)\MATLAB\R2010a Student\toolbox\matlab\datafun\@double\cumsum) % double method

built-in (C:\Program Files (x86)\MATLAB\R2010a Student\toolbox\matlab\datafun\@logical\cumsum) % logical method

built-in (C:\Program Files (x86)\MATLAB\R2010a Student\toolbox\matlab\datafun\@uint8\cumsum) % uint8 method

built-in (C:\Program Files (x86)\MATLAB\R2010a Student\toolbox\matlab\datafun\@int8\cumsum) % int8 method

built-in (C:\Program Files (x86)\MATLAB\R2010a Student\toolbox\matlab\datafun\@uint16\cumsum) % uint16 method

built-in (C:\Program Files (x86)\MATLAB\R2010a Student\toolbox\matlab\datafun\@int16\cumsum) % int16 method

built-in (C:\Program Files (x86)\MATLAB\R2010a Student\toolbox\matlab\datafun\@uint32\cumsum) % uint32 method

built-in (C:\Program Files (x86)\MATLAB\R2010a Student\toolbox\matlab\datafun\@int32\cumsum) % int32 method

Response to class (C) EDU>> class(C) ans = uint8

I have Matlab R2010a

Answer 1

[Image Analyst]

Try this. It works for me:

C = int32(randi(9, 1, 10))  % Array of integers.
A = 1 - cumsum(C)  / sum(C)

[per isakson]

The result of the division might come as a surprise

[Image Analyst]

Yes, MATLAB has an unintuitive of promoting/casting variable types. If C is double, it's fine. Regardless I can't find a way to duplicate the error the Ralph posted. Perhaps he can give some code that illustrates the error.

[Ralph]

The suggestion above to use int32() provided an idea on how to proceed. i did not know how to identify what format my data was in, so the class() command helped with this. My data was uint8. Do I used double() to change the format of my data, and I got passed the cumsum error. Thanks for the assistance.