Using 'single' arrays with the "filter" command

We have to minimize our application's memory footprint and execution time, so I'm trying to move from "double" data arrays to "single" data arrays. The problem is that the "filter" command appears to return "double" filter states. Is there a way to use "single" data with the filter or even the "conv" command?

[Matt J]

if your inputs are single, so should the output be.

Answer 1

[Jonathan Sullivan]

Make sure all your inputs to filter are singles.

Here's an example for a simple moving average:

x = rand(100,1,'single');
a = ones(1,10,'single')/single(10);
b = single(1);

xf = filter(a,b,x);

class(x)

[Jim Clay]

I have done that, but the second output, the final filter state, is still double.

Answer 2

[Jan]

See: FEX: FilterM, which accepts singles also.

Do you mean the 2nd output of filter with "double filter states"?

[Jim Clay]

Yes, I mean the 2nd output of filter. I will check out the FilterM command.