Developer Guide

This page contains additional information for people who want to extend acados.

Contributions

are handled via Pull Requests (PR) on Github

• Fork the project

• Push your changes to your fork

• Open a pull request https://github.com/acados/acados

• Describe what you changed and why.

• Rather make minimal changes

• Rather more commits than less

Memory management in acados

The following are guidelines on how memory should be assigned for an acados structure astruct.

There are two functions: astruct_calculate_size(), astruct_assign().

astruct_calculate_size()

Must return a multiple of 8 to keep the pointer aligned to 8 bytes when allocating substructures. Thus, it should end with:

    make_int_multiple_of(8, &size);

astruct_assign()

Should assign its members in the following order:

• Align to 8 bytes, i.e.:

    align_char_to(8, &c_ptr);

• Assign structure itself, i.e.:

    astruct *as_instance = (astruct *) c_ptr;
    c_ptr += sizeof(astruct);

• Assign pointers to substructures, if astruct contains an array of bstructs, e.g.

    mem->bstructs = (void **) c_ptr;
    c_ptr += N*sizeof(void *);

• Align to 8 bytes, since astruct might contain ints and the pointers were assigned.

• Assign “substructures”, i.e. structures that astruct has pointers to:

    // assume astruct contains an instance of bstruct
    as_instance->bstruct = bstruct_assign(c_ptr,...);
    c_ptr += bstruct_calculate_size(astruct);

• Note:

  • since calculate_size returns multiple of 8, c_ptr is still aligned to 8 bytes.

  • blasfeo_dmat_structs, blasfeo_dvec_structs can be seen as “substructures” here.

• Assign doubles (are 8 bytes anyway)

    assign_and_advance_double(n_doubles, &as_instance->doubles, &c_ptr);

• Assign pointers (4 bytes on 32 Bit)

    assign_and_advance_double_ptrs(n_pointers, &as_instance->double_pointer, &c_ptr);

• Align to 8 bytes, can be skipped if no pointers have been assigned

• Assign integers

    assign_and_advance_int(n_integers, &as_instance->ints, &c_ptr);

• Align to 64 bytes, i.e.:

    align_char_to(64, &c_ptr);

• Assign blasfeo_dmat_mem (are multiple of 64 Bytes)

    assign_and_advance_blasfeo_dmat_mem(nrow, ncol, &as_instance->blasfeo_mat, &c_ptr);

• Assign blasfeo_vec_mem (are multiple of 32 Bytes)

    assign_and_advance_blasfeo_dvec_mem(n, &as_instance->blasfeo_vec, &c_ptr);

• Align c_ptr to 8 byte here for nested assigns, see “substructures”

  • relevant if no blasfeo_mems are in astruct