"Non-constant or empty expression" error when generating code using imfilter

I'm trying to generate code from a function that uses imfilter like this:

function [output] = some_function(A)
%A is image data read in with imread
    conv_kern = 15;
    H = fspecial('disk', conv_kern);
    A_filtered = imfilter(A, H, 'replicate');
 ...

When the function runs through Coder it generates this error:

??? Non-constant expression or empty matrix. This expression must be constant because its value determines the size or class of some expression.

Error in ==> padarray Line: 213 Column: 34

The Coder settings have A defined as a specific size and data type, and I thought the other arguments (H and 'replicate') would be considered constant, so I'm confused where the error is coming from.

[Ryan Livingston]

Hi Christopher,

I tried this snippet in the pre-release and couldn't see the error either. Is it possible that some of the code after the posted snippet is having an effect?

Could you please run:

coder -tocode < name >.prj -script build_imfilter.m

where < name > is the name of your project and post build_imfilter.m? That will help us reproduce more easily.

[Vignesh]

If you are still having trouble, consider contacting MathWorks technical support http://www.mathworks.com/support/contact_us/

Answer 1

[Anand]

Could you say which release and platform you are working with? I'm not able to see this.

[Christopher McNally]

I'm running the 2014b pre-release candidate on Linux.

Answer 2

[Image Analyst]

Perhaps try conv2() instead of imfilter().