OK, further to my previous questions I'm having issues using arrays

It seems to be really hit and miss which is probablly what annoys me the most

I create a struct object with an array of floats, defined as

struct test-struct-template array a float

this is in a patcher called test-struct-template

i have a data window called array-struct-test-window

Im using setsize and getsize, passing them pointers and then sending or recieving floats. If i copy/paste the example in the help file then i can get it working, but if i try to build it from scratch then i get empty pointer errors. I just cant seem to get to the bottom of it.

any help would be much appreciated, i've attached a test patch to show what im trying to do. i'm guessing its just something very simple and obvious.... at least i hope it is heh

http://www.pdpatchrepo.info/hurleur/arraystructwut.pd

well, the pointer is empty because you didn't append any array in the data window. data structures, you know...

and to define an array, you need a struct for the array plus a struct for the elements the array contains. then it should work.

ah ok, so essentially if i want to have a data structure that holds 8 arrays of floats i need to.

Define a struct and have the arrays defined as being another struct type eg:-
struct track-info-template array a float-struct array b float-struct etc....

and then in seperate sub patches in the main patch have structs which define float-struct thusly :-
struct float-struct float

then i need to append these onto the data window to create them, and then from there i can resize them/use them etc??

did i miss the documentation for this or is it just not written down anywhere?? i'm genuinly tempted to take all this knowledge and try and put together a comprehensive tutorial explaining all this.

hhhmmm, i dont seem to be having any luck with this. do i need to create a new template/struct for each array in the main struct??

i keep getting empty pointer objects.

scratch that, 5 minutes of testing and i seem to have it working. not sure why, i may well have more questions in a moment or two

Right, i think i've worked this out, but im not sure why it works like it does.....

I create a struct that has 8 arrays in it. the arrays are called a to h and all are of type float-struct.

float struct is a second struct which is just a float with a variable y

I need to set up an append object, naming the main struct and then any of the arrays. i send a number to that and get.

error: pd-mv-track-info.a: not a number

once this is done i can use set size on each of the arrays a through h within the struct and change their size fine. I'm really glad i got this working but i dont really get what the deal with the append object is, why i only have to name one of the arrays with it, and why i get the error message?

as always, anything that helps me make sense of this appreciated

hhhmm, i've just started looking into converting the step sequencer to use arrays and i've realised that actually i dont think its the best way to go about doing it.

getting data out of the arrays just seems a couple steps more complex than just dealing with lists of 128 scalars and so i think i'll leave these as they are.

I'm planning on making some sort of MIDI CC control sequencer and i suspect that for them the arrays will be perfect but for the moment, i'm happy with what i've got.

I'll try to put together some sort of learning patch that better explains whats in the help files

@tasteforreality said:

Right, i think i've worked this out, but im not sure why it works like it does.....

as always, anything that helps me make sense of this appreciated

Yo Taste,

I came across this thread while trying to figure out how to put arrays into data struct's, to make visual scores like miller and han's, but was having about the same trouble as you. I found this yesterday and figured i'd post it:

http://www.pd-tutorial.com/english/ch05s02.html#chapt5.2.3

this tut is kindof obscured in the back of the online text's miscellaneous section, so i didn't find it before i found your post.

Hope it helps you or anyone else.

-Cheers

hey, thanks for the heads up, looks useful. I need to read more of pd-tutorial.

i'd actually forgotten about this post, i put together the sequencer i was planning to build but it wasn't as good as i was hoping, partly due to less than stellar hardware.

I know i somewhat got the hang of data structures but can't remember much of them now. I should probably have a look at them again. I might actually try and write up a couple of useful tutorials on them since the info that really explains them still seems to be spread about a bit.

The most comprehensive datastructure tutorial I found was this one:
http://puredata.info/Members/ggkarman/Tutoriales/datastruct_en_02/view