Feature Request: Allow each row, within a 'loop,' to run different 'sequence.'

andersony3k

Feature Request: Allow each row, within a 'loop,' to run different 'sequence.' This would permit easy randomization (i.e., without the user having to write code) of the order in which distinct blocks of trials occur (and would match the capability of another, well-known, proprietary experiment builder).

sebastiaan

Hi,

In principle, this is already possible by having a structure like the one below, where you use an Run If statement to select a sequence. But it does require one additional layer (outer_sequence) in the structure.

How would you like to see this implemented? And would there be any real advantage over the current way?

Cheers!
Sebastiaan

andersony3k

Thanks. That solution had not occurred to me with regard to randomizing the order of different sequences (as opposed to randomly selecting which sequence(s) to run or not run).

But suppose I have inner_sequence_1, inner_sequence_2, inner_sequence_3, inner_sequence_4, inner_sequence_5, inner_sequence_6, inner_sequence_7, inner_sequence_8, inner_sequence_9, inner_sequence_10, and I want to run a random _ordering of the sequences.

The solution you provide above would not work in that case.

I believe these are previously suggested solutions involving in-line code:
http://www.cogsci.nl/forum/index.php?p=/discussion/144/solved-randomizing-a-sequence-of-four-blocks
http://forum.cogsci.nl/index.php?p=/discussion/2580/how-to-randomize-blocks-in-opensesame-a-solution-not-a-question

However, I illustrate below how the process can be simplified from the researchers point of view, by allowing the run 'item' to be loop row specific, rather than loop-specific:

andersony3k

And the tree representation would look like this:

sebastiaan

But suppose I have inner_sequence_1, inner_sequence_2, inner_sequence_3, inner_sequence_4, inner_sequence_5, inner_sequence_6, inner_sequence_7, inner_sequence_8, inner_sequence_9, inner_sequence_10, and I want to run a random _ordering of the sequences. The solution you provide above would not work in that case.

It would because you can simply have multiple rows in block_loop with different values for condition. But it would not be very elegant, in that I agree.

I'll think about a good solution for this use case. One thing that comes to mind is simply to allow variables in the run … statement of a loop. Right now this only works with a literal item name.

andersony3k

OK. Thanks! I now see how the RUN IF functionality, combined with sequence-within-a-sequence, can indeed randomly order the blocks/inner-sequences. So it's not necessary to implement the feature I requested. Perhaps adding a section on it, in the documentation, would be useful. Currently, I see that in the forum, people are assuming that block/sequence randomization can only be done via Python script.