Empty output when using Iterative Yang

[JuliaHilgers]

Hi,
I try to use the Iterative Yang method for pvc, but have problems with the output.
Whenever using the IY or IY-based pvc as method the output image is empty. By changing the method to RBV+VC it works perfectly.
I checked the inputs and they should be correct (also as they seem to work for the RBV+VC method). The PET input image is of size 256x256x153x1 and the mask file 256x256x153x3 with voxel size of 1.25 mm.
The debug output looks like this:

matrix:
1 0.139333 0.476918 
0.000474744 0.573128 0.379844 
0.00119729 0.279869 0.587275 


Iteration:  
1  0.639636 14.6091 20.8643
2  -nan -nan -nan
3  -nan -nan -nan
4  -nan -nan -nan
5  -nan -nan -nan
6  -nan -nan -nan
7  -nan -nan -nan
8  -nan -nan -nan
9  -nan -nan -nan
10  -nan -nan -nan

Could there be any issue with the code or do you have another idea why this happens?

Best regards,
Julia