Martin Beck

Hello, I would like to reshape a [jit.matrix 3 float32 a b c] into a [jit.matrix 3 float32 a*b*c]. I thought [jit.scanwrap] would be suitable for this, but it doesn't work (see attached patch). It seems to handle the third dimension c wrong. Is there a jit object that can convert a 3-dimensional 3 plane matrix into a 1-dimensional 3 plane matrix? Using [jit.spill] and [jit.fill] also doesn't work - 3 dimensional matrices seem to be a problem for a lot of jitter objects. Javascript solution to this is not sufficiently performant.

speedlim

loadbang

message

route

jit.matrixinfo

comment

jit.gen

jit.gl.gridshape

jit.gl.multiple

attrui

jit.scanwrap

jit.gl.handle

button

snorm

jit.matrix

toggle

jit.fpsgui

jit.world

jit.pwindow

jit.unpack

Hello, I would like to reshape a [jit.matrix 3 float32 a b c] into a  [jit.matrix 3 float32 a*b*c]. I thought [jit.scanwrap] would be suitable for this, but it doesn't work (see attached patch). It seems to  handle the third dimension c wrong. Is there a jit object that can convert a 3-dimensional 3 plane matrix into a 1-dimensional 3 plane matrix? Using [jit.spill] and [jit.fill] also doesn't work - 3 dimensional matrices seem to be a problem for a lot of jitter objects. Javascript solution to this is not sufficiently performant.


Hello, I would like to reshape a [jit.matrix 3 float32 a b c] into a  [jit.matrix 3 float32 a*b*c]. I thought [jit.scanwrap] would be suitab

matrix-reshaping

Wouldn't you have to use a 1 plane matrix for that? [jit.matrix 1 float32 (a*b*c)] you can always bring in the matrix into gen swiz it to unpack each vector, multiply them by themselves and then pass out to a 1 plane matrix. Maybe this helps?

...question was related to reshaping the matrix from 3 to 1 dimension while not affecting the planes, not to perform products of its elements.

I never tried jit.scanwrap with more than 2 dimensions before, but it seems indeed limited to 2 dimensions. Looks like it's not documented (couldn't find this limit in the Reference?)

Best thing I managed till now is this one. A good thing is that [jit.submatrix] does not copy data to a new matrix but just gives a reference to the corresponding part of the input matrix (AFAIK).

Bad thing: you need as many [jit.submatrix] objects as one of the dimensions. (Note that I'm assuming here that you want to process that in Max, not in GPU world.)

Martin, that's an interesting question.
I never tried jit.scanwrap with more than 2 dimensions before, but it seems indeed limited to 2 dimensions. Looks like it's not documented (couldn't find this limit in the Reference?)
Best thing I managed till now is this one. A good thing is that [jit.submatrix] does not copy data to a new matrix but just gives a reference to the corresponding part of the input matrix (AFAIK).
Bad thing: you need as many [jit.submatrix] objects as one of the dimensions. (Note that I'm assuming here that you want to process that in Max, not in GPU world.)

Variation on the idea, adapting to the dimension, using just one [jit.submatrix]:

Or with adaption to all three dimensions:

sorry I don't have time to work this out myself to post an example but I wonder if the dimmap object could be part of the solution. could you iterate through the z dim and use the scan wrap in fill mode to wait for enough data to send out a 1d matrix? the 3d slice tab in the jit.dimmap help might give a hint on getting 2d slices from the 3d matrix

Thanks a lot for all the ideas - I will take a look. Just in case someone is also interested in the javascript version for 3D I share it here. Looks like an implementation in C might be not too difficult...

var size = threeD.dim[0] * threeD.dim[1] * threeD.dim[2];

var OneD = new JitterMatrix(3, "float32", size);

Thanks a lot for all the ideas -  I will take a look. Just in case someone is also interested in the javascript version for 3D I share it here. Looks like an implementation in C might be not too difficult...

matrix reshaping