[REQ] Storing a sparse matrix in a warp struct

[itsvismay]

Description

I'm trying to create a warp struct that holds a sparse matrix:

@wp.struct
class NeohookeanElasticMaterial:
    sparse_hessian: wps.bsr_matrix_t(dtype=wp.types.matrix(shape=(9,9), dtype=wp.float32))

Context

Setting the sparse matrix shape during construction as follows;

neohookean_struct = NeohookeanElasticMaterial()
neohookean_struct.sparse_hessian = wps.bsr_zeros(
        N, N, block_type=wp.types.matrix(shape=(9, 9), dtype=wp.float32), device=device)

And finally setting its values within the hessian function as: wps.bsr_set_diag(neohookean_struct.sparse_hessian,hessian_blocks) I get an error saying: AttributeError: 'StructInstance' object has no attribute 'copy_nnz_async'

[shi-eric]

@gdaviet added a fix for this in 87e843b544f715116c275681c1c39457f483e95c

Previously creating a struct instance with the call operator would inherit the attributes from the Python base class, but this was not the case for instances crated as nested attributes of a parent struct. This fixes this discrepancy, and in particular allows the use of wp.sparse.BsrMatrix helper properties on nested attributes.

Please give it a try by building Warp from source or installing a nightly build. It will be included in Warp 1.8.0.