Crate tenferro_capi 

C-API (FFI) for tenferro.

Exposes tensor lifecycle, einsum, SVD (including AD rules), and DLPack interop to host languages such as Julia, Python (JAX, PyTorch), and C/C++.

Design principles

• Opaque pointers: TfeTensorF64 is an opaque handle wrapping Tensor<f64>. Host languages never see Rust internals.
• Status codes: Every function takes a *mut tfe_status_t as its last argument. Rust panics are caught with catch_unwind and converted to TFE_INTERNAL_ERROR.
• Stateless AD rules: Only rrule (VJP) and frule (JVP) are exposed. The AD tape / TrackedValue / DualValue are Rust-internal and not exposed via FFI.
• f64 only in this POC phase. All functions carry the _f64 suffix.
• DLPack interop: Zero-copy tensor exchange via DLManagedTensorVersioned.
• Copy semantics for convenience functions: tfe_tensor_f64_from_data copies the caller’s data into a Rust-owned buffer.

Header generation

cbindgen --config cbindgen.toml --crate tenferro-capi --output tenferro.h

Examples

tfe_status_t status;
size_t shape[] = {3, 4};
double data[12] = { /* ... */ };
tfe_tensor_f64 *a = tfe_tensor_f64_from_data(data, 12, shape, 2, &status);
const tfe_tensor_f64 *ops[] = {a, a};
tfe_tensor_f64 *c = tfe_einsum_f64("ij,jk->ik", ops, 2, &status);
tfe_tensor_f64_release(c);
tfe_tensor_f64_release(a);

Structs

DLDataType

DLPack data type descriptor.

DLDevice

DLPack device descriptor.

DLManagedTensorVersioned

DLPack managed tensor with version and ownership.

DLPackVersion

DLPack version information.

DLTensor

DLPack tensor descriptor (unmanaged).

TfeTensorF64

Opaque handle wrapping a Tensor<f64>.

Constants

DLPACK_FLAG_BITMASK_IS_COPIED

Data was copied.

DLPACK_FLAG_BITMASK_READ_ONLY

Data is read-only.

KDLCOMPLEX

Complex type code.

KDLCPU

CPU device.

KDLCUDA

NVIDIA CUDA GPU device memory.

KDLCUDA_HOST

Pinned CUDA CPU memory.

KDLCUDA_MANAGED

CUDA managed/unified memory.

KDLFLOAT

Floating-point type code.

KDLINT

Integer type code.

KDLROCM

AMD ROCm GPU device memory.

KDLROCM_HOST

Pinned ROCm CPU memory.

TFE_BUFFER_TOO_SMALL

Output buffer is too small for the requested data.

TFE_INTERNAL_ERROR

Internal error (Rust panic or unexpected failure).

TFE_INVALID_ARGUMENT

Invalid argument (null pointer, bad subscript string, etc.).

TFE_SHAPE_MISMATCH

Tensor shape mismatch for the requested operation.

TFE_SUCCESS

Operation completed successfully.

Functions

tfe_einsum_f64^⚠

Execute einsum using string notation.

tfe_einsum_frule_f64^⚠

Forward-mode rule (JVP) for einsum.

tfe_einsum_rrule_f64^⚠

Reverse-mode rule (VJP) for einsum.

tfe_last_error_message^⚠

Retrieve the last error message (UTF-8, null-terminated).

tfe_svd_f64^⚠

Compute the SVD of a tensor after matricizing by left and right.

tfe_svd_frule_f64^⚠

Forward-mode rule (JVP) for SVD.

tfe_svd_rrule_f64^⚠

Reverse-mode rule (VJP) for SVD.

tfe_tensor_f64_clone^⚠

Deep-copy a tensor.

tfe_tensor_f64_data^⚠

Return a pointer to the tensor’s raw data buffer.

tfe_tensor_f64_from_data^⚠

Create a tensor from caller-provided data (copy semantics).

tfe_tensor_f64_from_dlpack^⚠

Import a DLPack managed tensor as a tenferro tensor (zero-copy).

tfe_tensor_f64_len^⚠

Return the total number of elements in the tensor.

tfe_tensor_f64_ndim^⚠

Return the number of dimensions (rank) of the tensor.

tfe_tensor_f64_release^⚠

Release (free) a tensor.

tfe_tensor_f64_shape^⚠

Write the shape of the tensor into the caller-provided buffer.

tfe_tensor_f64_to_dlpack^⚠

Export a tensor as a DLPack managed tensor (zero-copy).

tfe_tensor_f64_zeros^⚠

Create a tensor filled with zeros.

Type Aliases

tfe_status_t

Status code type returned by all C-API functions.