Why 'parallel' changes output?

Software G'MIC
1

Hello there.

My set up is gmic 2.0.0 (a very old version I compiled myself) and a dual core old computer.

I would like to get help with 2 questions I got, please.

Why when parallel is present the output is like ‘split’? Just like if gmic splits the image and sends the pieces to each core and once finished they are just “glued” together.

How to stop it from “putting” a “line” in the middle of the picture?

Basically is with any filter, if I select the processing to be done with 2 cores at the same time. It does takes half the time to get a result, compared with a single core but is not the same.

This is the image I’m processing with a single core.

image--027.noartifacts.gmic
image--027.noartifacts.gmic1200×1098 251 KB

If two cores are used, a “line” (or the “boundary of each slice”) is shown in the middle of the picture (check mouth and nose).

28.artifacts.gmic
28.artifacts.gmic2400×2205 631 KB

Thank you. :slight_smile:

2

Please update.

And your explanation is on point. Sometimes, it’s possible to have parallel output to output the same as if it were as if it single thread. Sometimes, it is not.

1 Like
3

Thank you, I’ll be compiling the most updated version.

And, what can I do to get more chances to get a “good looking” output.

4

Any ideas?