from keras.src import backend from keras.src import tree from keras.src.api_export import keras_export from keras.src.backend import KerasTensor from keras.src.backend import any_symbolic_tensors from keras.src.ops.operation import Operation from keras.src.ops.operation_utils import reduce_shape class Cholesky(Operation): def __init__(self, upper=False, *, name=None): super().__init__(name=name) self.upper = upper def call(self, x): return _cholesky(x, self.upper) def compute_output_spec(self, x): _assert_2d(x) _assert_square(x) return KerasTensor(x.shape, x.dtype) @keras_export(["keras.ops.cholesky", "keras.ops.linalg.cholesky"]) def cholesky(x, upper=False): """Computes the Cholesky decomposition of a positive semi-definite matrix. Args: x: Input tensor of shape `(..., M, M)`. upper (bool): If True, returns the upper-triangular Cholesky factor. If False (default), returns the lower-triangular Cholesky factor. Returns: A tensor of shape `(..., M, M)` representing the Cholesky factor of `x`. """ if any_symbolic_tensors((x,)): return Cholesky(upper=upper).symbolic_call(x) return _cholesky(x, upper=upper) def _cholesky(x, upper=False): x = backend.convert_to_tensor(x) _assert_2d(x) _assert_square(x) try: return backend.linalg.cholesky(x, upper=upper) except Exception as e: raise ValueError(f"Cholesky decomposition failed: {e}") class CholeskyInverse(Operation): def __init__(self, upper=False, *, name=None): super().__init__(name=name) self.upper = upper def call(self, x): return _cholesky_inverse(x, self.upper) def compute_output_spec(self, x): _assert_2d(x) _assert_square(x) return KerasTensor(x.shape, x.dtype) @keras_export( ["keras.ops.cholesky_inverse", "keras.ops.linalg.cholesky_inverse"] ) def cholesky_inverse(x, upper=False): """Computes the inverse of a symmetric positive-definite matrix. Args: x: Input tensor of shape `(..., M, M)`. upper (bool): Determines whether to use the upper- or lower-triangular factor for the internal computation. Defaults to False. Returns: A tensor of shape `(..., M, M)` representing the inverse of `x`. Raises: ValueError: If `x` is not a symmetric positive-definite matrix. """ if any_symbolic_tensors((x,)): return CholeskyInverse(upper=upper).symbolic_call(x) return _cholesky_inverse(x, upper=upper) def _cholesky_inverse(x, upper=False): x = backend.convert_to_tensor(x) _assert_2d(x) _assert_square(x) try: return backend.linalg.cholesky_inverse(x, upper=upper) except Exception as e: raise ValueError(f"Cholesky inverse failed: {e}") class Det(Operation): def call(self, x): return _det(x) def compute_output_spec(self, x): _assert_2d(x) _assert_square(x) return KerasTensor(x.shape[:-2], x.dtype) @keras_export(["keras.ops.det", "keras.ops.linalg.det"]) def det(x): """Computes the determinant of a square tensor. Args: x: Input tensor of shape `(..., M, M)`. Returns: A tensor of shape `(...,)` representing the determinant of `x`. """ if any_symbolic_tensors((x,)): return Det().symbolic_call(x) return _det(x) def _det(x): x = backend.convert_to_tensor(x) _assert_2d(x) _assert_square(x) return backend.linalg.det(x) class Eig(Operation): def call(self, x): return _eig(x) def compute_output_spec(self, x): _assert_square(x) _assert_2d(x) return ( KerasTensor(x.shape[:-1], x.dtype), KerasTensor(x.shape, x.dtype), ) @keras_export(["keras.ops.eig", "keras.ops.linalg.eig"]) def eig(x): """Computes the eigenvalues and eigenvectors of a square matrix. Args: x: Input tensor of shape `(..., M, M)`. Returns: A tuple of two tensors: a tensor of shape `(..., M)` containing eigenvalues and a tensor of shape `(..., M, M)` containing eigenvectors. """ if any_symbolic_tensors((x,)): return Eig().symbolic_call(x) return _eig(x) def _eig(x): x = backend.convert_to_tensor(x) _assert_square(x) _assert_2d(x) return backend.linalg.eig(x) class Eigh(Operation): def call(self, x): return _eigh(x) def compute_output_spec(self, x): _assert_square(x) _assert_2d(x) return ( KerasTensor(x.shape[:-1], x.dtype), KerasTensor(x.shape, x.dtype), ) @keras_export(["keras.ops.eigh", "keras.ops.linalg.eigh"]) def eigh(x): """Computes the eigenvalues and eigenvectors of a complex Hermitian. Args: x: Input tensor of shape `(..., M, M)`. Returns: A tuple of two tensors: a tensor of shape `(..., M)` containing eigenvalues and a tensor of shape `(..., M, M)` containing eigenvectors. """ if any_symbolic_tensors((x,)): return Eigh().symbolic_call(x) return _eigh(x) def _eigh(x): x = backend.convert_to_tensor(x) _assert_square(x) _assert_2d(x) return backend.linalg.eigh(x) class Inv(Operation): def call(self, x): return _inv(x) def compute_output_spec(self, x): _assert_2d(x) _assert_square(x) return KerasTensor(x.shape, x.dtype) @keras_export(["keras.ops.inv", "keras.ops.linalg.inv"]) def inv(x): """Computes the inverse of a square tensor. Args: x: Input tensor of shape `(..., M, M)`. Returns: A tensor of shape `(..., M, M)` representing the inverse of `x`. """ if any_symbolic_tensors((x,)): return Inv().symbolic_call(x) return _inv(x) def _inv(x): x = backend.convert_to_tensor(x) _assert_2d(x) _assert_square(x) return backend.linalg.inv(x) class LuFactor(Operation): def call(self, x): return _lu_factor(x) def compute_output_spec(self, x): _assert_2d(x) batch_shape = x.shape[:-2] m, n = x.shape[-2:] k = min(m, n) return ( KerasTensor(batch_shape + (m, n), x.dtype), KerasTensor(batch_shape + (k,), x.dtype), ) @keras_export(["keras.ops.lu_factor", "keras.ops.linalg.lu_factor"]) def lu_factor(x): """Computes the lower-upper decomposition of a square matrix. Args: x: A tensor of shape `(..., M, M)`. Returns: A tuple of two tensors: a tensor of shape `(..., M, M)` containing the lower and upper triangular matrices and a tensor of shape `(..., M)` containing the pivots. """ if any_symbolic_tensors((x,)): return LuFactor().symbolic_call(x) return _lu_factor(x) def _lu_factor(x): x = backend.convert_to_tensor(x) _assert_2d(x) if backend.backend() == "tensorflow": try: _assert_square(x) except ValueError as e: raise ValueError( f"LU decomposition failed: {e}. LU decomposition is only " "supported for square matrices in Tensorflow." ) return backend.linalg.lu_factor(x) class Norm(Operation): def __init__(self, ord=None, axis=None, keepdims=False, *, name=None): super().__init__(name=name) if isinstance(ord, str): if ord not in ("fro", "nuc"): raise ValueError( "Invalid `ord` argument. " "Expected one of {'fro', 'nuc'} when using string. " f"Received: ord={ord}" ) if isinstance(axis, int): axis = [axis] self.ord = ord self.axis = axis self.keepdims = keepdims def compute_output_spec(self, x): output_dtype = backend.standardize_dtype(x.dtype) if "int" in output_dtype or output_dtype == "bool": output_dtype = backend.floatx() if self.axis is None: axis = tuple(range(len(x.shape))) else: axis = self.axis num_axes = len(axis) if num_axes == 1 and isinstance(self.ord, str): raise ValueError( "Invalid `ord` argument for vector norm. " f"Received: ord={self.ord}" ) elif num_axes == 2 and self.ord not in ( None, "fro", "nuc", float("inf"), float("-inf"), 1, -1, 2, -2, ): raise ValueError( "Invalid `ord` argument for matrix norm. " f"Received: ord={self.ord}" ) return KerasTensor( reduce_shape(x.shape, axis=self.axis, keepdims=self.keepdims), dtype=output_dtype, ) def call(self, x): x = backend.convert_to_tensor(x) return backend.linalg.norm( x, ord=self.ord, axis=self.axis, keepdims=self.keepdims ) @keras_export(["keras.ops.norm", "keras.ops.linalg.norm"]) def norm(x, ord=None, axis=None, keepdims=False): """Matrix or vector norm. This function is able to return one of eight different matrix norms, or one of an infinite number of vector norms (described below), depending on the value of the `ord` parameter. Args: x: Input tensor. ord: Order of the norm (see table under Notes). The default is `None`. axis: If `axis` is an integer, it specifies the axis of `x` along which to compute the vector norms. If `axis` is a 2-tuple, it specifies the axes that hold 2-D matrices, and the matrix norms of these matrices are computed. keepdims: If this is set to `True`, the axes which are reduced are left in the result as dimensions with size one. Note: For values of `ord < 1`, the result is, strictly speaking, not a mathematical 'norm', but it may still be useful for various numerical purposes. The following norms can be calculated: - For matrices: - `ord=None`: Frobenius norm - `ord="fro"`: Frobenius norm - `ord="nuc"`: nuclear norm - `ord=np.inf`: `max(sum(abs(x), axis=1))` - `ord=-np.inf`: `min(sum(abs(x), axis=1))` - `ord=0`: not supported - `ord=1`: `max(sum(abs(x), axis=0))` - `ord=-1`: `min(sum(abs(x), axis=0))` - `ord=2`: 2-norm (largest sing. value) - `ord=-2`: smallest singular value - other: not supported - For vectors: - `ord=None`: 2-norm - `ord="fro"`: not supported - `ord="nuc"`: not supported - `ord=np.inf`: `max(abs(x))` - `ord=-np.inf`: `min(abs(x))` - `ord=0`: `sum(x != 0)` - `ord=1`: as below - `ord=-1`: as below - `ord=2`: as below - `ord=-2`: as below - other: `sum(abs(x)**ord)**(1./ord)` Returns: Norm of the matrix or vector(s). Example: >>> x = keras.ops.reshape(keras.ops.arange(9, dtype="float32") - 4, (3, 3)) >>> keras.ops.linalg.norm(x) 7.7459664 """ if any_symbolic_tensors((x,)): return Norm(ord=ord, axis=axis, keepdims=keepdims).symbolic_call(x) x = backend.convert_to_tensor(x) return backend.linalg.norm(x, ord=ord, axis=axis, keepdims=keepdims) class Qr(Operation): def __init__(self, mode="reduced", *, name=None): super().__init__(name=name) if mode not in {"reduced", "complete"}: raise ValueError( "`mode` argument value not supported. " "Expected one of {'reduced', 'complete'}. " f"Received: mode={mode}" ) self.mode = mode def compute_output_spec(self, x): if len(x.shape) < 2: raise ValueError( "Input should have rank >= 2. Received: " f"input.shape = {x.shape}" ) m = x.shape[-2] n = x.shape[-1] if m is None or n is None: raise ValueError( "Input should have its last 2 dimensions " "fully-defined. Received: " f"input.shape = {x.shape}" ) k = min(m, n) base = tuple(x.shape[:-2]) if self.mode == "reduced": return ( KerasTensor(shape=base + (m, k), dtype=x.dtype), KerasTensor(shape=base + (k, n), dtype=x.dtype), ) # 'complete' mode. return ( KerasTensor(shape=base + (m, m), dtype=x.dtype), KerasTensor(shape=base + (m, n), dtype=x.dtype), ) def call(self, x): x = backend.convert_to_tensor(x) return backend.linalg.qr(x, mode=self.mode) @keras_export(["keras.ops.qr", "keras.ops.linalg.qr"]) def qr(x, mode="reduced"): """Computes the QR decomposition of a tensor. Args: x: Input tensor of shape `(..., M, N)`. mode: A string specifying the mode of the QR decomposition. - 'reduced': Returns the reduced QR decomposition. (default) - 'complete': Returns the complete QR decomposition. Returns: A tuple containing two tensors. The first tensor of shape `(..., M, K)` is the orthogonal matrix `q` and the second tensor of shape `(..., K, N)` is the upper triangular matrix `r`, where `K = min(M, N)`. Example: >>> x = keras.ops.convert_to_tensor([[1., 2.], [3., 4.], [5., 6.]]) >>> q, r = qr(x) >>> print(q) array([[-0.16903079 0.897085] [-0.5070925 0.2760267 ] [-0.8451542 -0.34503305]], shape=(3, 2), dtype=float32) """ if any_symbolic_tensors((x,)): return Qr(mode=mode).symbolic_call(x) x = backend.convert_to_tensor(x) return backend.linalg.qr(x, mode=mode) class Solve(Operation): def call(self, a, b): return _solve(a, b) def compute_output_spec(self, a, b): _assert_2d(a) _assert_square(a) _assert_1d(b) _assert_a_b_compat(a, b) return KerasTensor(b.shape, b.dtype) @keras_export(["keras.ops.solve", "keras.ops.linalg.solve"]) def solve(a, b): """Solves a linear system of equations given by `a x = b`. Args: a: A tensor of shape `(..., M, M)` representing the coefficients matrix. b: A tensor of shape `(..., M)` or `(..., M, N)` representing the right-hand side or "dependent variable" matrix. Returns: A tensor of shape `(..., M)` or `(..., M, N)` representing the solution of the linear system. Returned shape is identical to `b`. """ if any_symbolic_tensors((a, b)): return Solve().symbolic_call(a, b) return _solve(a, b) def _solve(a, b): a = backend.convert_to_tensor(a) b = backend.convert_to_tensor(b) _assert_2d(a) _assert_square(a) _assert_1d(b) _assert_a_b_compat(a, b) return backend.linalg.solve(a, b) class SolveTriangular(Operation): def __init__(self, lower=False, *, name=None): super().__init__(name=name) self.lower = lower def call(self, a, b): return _solve_triangular(a, b, self.lower) def compute_output_spec(self, a, b): _assert_2d(a) _assert_square(a) _assert_1d(b) _assert_a_b_compat(a, b) return KerasTensor(b.shape, b.dtype) @keras_export( ["keras.ops.solve_triangular", "keras.ops.linalg.solve_triangular"] ) def solve_triangular(a, b, lower=False): """Solves a linear system of equations given by `a x = b`. Args: a: A tensor of shape `(..., M, M)` representing the coefficients matrix. b: A tensor of shape `(..., M)` or `(..., M, N)` representing the right-hand side or "dependent variable" matrix. Returns: A tensor of shape `(..., M)` or `(..., M, N)` representing the solution of the linear system. Returned shape is identical to `b`. """ if any_symbolic_tensors((a, b)): return SolveTriangular(lower).symbolic_call(a, b) return _solve_triangular(a, b, lower) def _solve_triangular(a, b, lower=False): a = backend.convert_to_tensor(a) b = backend.convert_to_tensor(b) _assert_2d(a) _assert_square(a) _assert_1d(b) _assert_a_b_compat(a, b) return backend.linalg.solve_triangular(a, b, lower) class SVD(Operation): def __init__(self, full_matrices=True, compute_uv=True, *, name=None): super().__init__(name=name) self.full_matrices = full_matrices self.compute_uv = compute_uv def call(self, x): return _svd(x, self.full_matrices, self.compute_uv) def compute_output_spec(self, x): _assert_2d(x) rows, columns = x.shape[-2:] batches = x.shape[:-2] s_shape = batches + (min(rows, columns),) if self.full_matrices: u_shape = batches + (rows, rows) v_shape = batches + (columns, columns) else: u_shape = batches + (rows, min(rows, columns)) v_shape = batches + (min(rows, columns), columns) if self.compute_uv: return ( KerasTensor(u_shape, x.dtype), KerasTensor(s_shape, x.dtype), KerasTensor(v_shape, x.dtype), ) return KerasTensor(s_shape, x.dtype) @keras_export(["keras.ops.svd", "keras.ops.linalg.svd"]) def svd(x, full_matrices=True, compute_uv=True): """Computes the singular value decomposition of a matrix. Args: x: Input tensor of shape `(..., M, N)`. Returns: A tuple of three tensors: a tensor of shape `(..., M, M)` containing the left singular vectors, a tensor of shape `(..., M, N)` containing the singular values and a tensor of shape `(..., N, N)` containing the right singular vectors. """ if any_symbolic_tensors((x,)): return SVD(full_matrices, compute_uv).symbolic_call(x) return _svd(x, full_matrices, compute_uv) def _svd(x, full_matrices=True, compute_uv=True): x = backend.convert_to_tensor(x) _assert_2d(x) return backend.linalg.svd(x, full_matrices, compute_uv) class Lstsq(Operation): def __init__(self, rcond=None, *, name=None): super().__init__(name=name) self.rcond = rcond def call(self, a, b): return backend.linalg.lstsq(a, b, rcond=self.rcond) def compute_output_spec(self, a, b): if len(a.shape) != 2: raise ValueError( f"Expected a to have rank 2. Received: a.shape={a.shape}" ) if len(b.shape) not in (1, 2): raise ValueError( f"Expected b to have rank 1 or 2. Received: b.shape={b.shape}" ) m, n = a.shape if b.shape[0] != m: raise ValueError( "Expected b.shape[0] to be equal to " "a.shape[0]. Received: " f"a.shape={a.shape}, b.shape={b.shape}" ) if len(b.shape) == 2: k = b.shape[1] x = KerasTensor((n, k), dtype=a.dtype) else: x = KerasTensor((n,), dtype=a.dtype) return x @keras_export(["keras.ops.lstsq", "keras.ops.linalg.lstsq"]) def lstsq(a, b, rcond=None): """Return the least-squares solution to a linear matrix equation. Computes the vector x that approximately solves the equation `a @ x = b`. The equation may be under-, well-, or over-determined (i.e., the number of linearly independent rows of a can be less than, equal to, or greater than its number of linearly independent columns). If a is square and of full rank, then `x` (but for round-off error) is the exact solution of the equation. Else, `x` minimizes the L2 norm of `b - a * x`. If there are multiple minimizing solutions, the one with the smallest L2 norm is returned. Args: a: "Coefficient" matrix of shape `(M, N)`. b: Ordinate or "dependent variable" values, of shape `(M,)` or `(M, K)`. If `b` is two-dimensional, the least-squares solution is calculated for each of the K columns of `b`. rcond: Cut-off ratio for small singular values of `a`. For the purposes of rank determination, singular values are treated as zero if they are smaller than rcond times the largest singular value of `a`. Returns: Tensor with shape `(N,)` or `(N, K)` containing the least-squares solutions. **NOTE:** The output differs from `numpy.linalg.lstsq`. NumPy returns a tuple with four elements, the first of which being the least-squares solutions and the others being essentially never used. Keras only returns the first value. This is done both to ensure consistency across backends (which cannot be achieved for the other values) and to simplify the API. """ if any_symbolic_tensors((a, b)): return Lstsq(rcond=rcond).symbolic_call(a, b) return backend.linalg.lstsq(a, b, rcond=rcond) def _assert_1d(*arrays): for a in arrays: if a.ndim < 1: raise ValueError( f"Expected input to have rank >= 1. Received scalar input {a}." ) def _assert_2d(*arrays): for a in arrays: if a.ndim < 2: raise ValueError( "Expected input to have rank >= 2. " f"Received input with shape {a.shape}." ) def _assert_square(*arrays): for a in arrays: m, n = a.shape[-2:] if m != n: raise ValueError( "Expected a square matrix. " f"Received non-square input with shape {a.shape}" ) def _assert_a_b_compat(a, b): if a.ndim == b.ndim: if a.shape[-2] != b.shape[-2]: raise ValueError( "Incompatible shapes between `a` and `b`. " "Expected `a.shape[-2] == b.shape[-2]`. " f"Received: a.shape={a.shape}, b.shape={b.shape}" ) elif a.ndim == b.ndim - 1: if a.shape[-1] != b.shape[-1]: raise ValueError( "Incompatible shapes between `a` and `b`. " "Expected `a.shape[-1] == b.shape[-1]`. " f"Received: a.shape={a.shape}, b.shape={b.shape}" ) class JVP(Operation): def __init__(self, has_aux=False, *, name=None): super().__init__(name=name) self.has_aux = has_aux def call(self, fun, primals, tangents): """Computes the JVP of `fun` at `primals` along `tangents`. Args: fun: A callable that takes tensors (or nested structures) as input and returns a tensor (or nested structure) as output. primals: Input tensors (or nested structures) at which the Jacobian of `fun` is evaluated. tangents: Tensors (or nested structures) representing the direction vectors for the JVP. Must have the same structure as `primals`. Returns: If `has_aux` is False: A tuple (primals_out, tangents_out) where: - primals_out: Output of `fun(*primals)` - tangents_out: JVP of `fun` at `primals` along `tangents` If `has_aux` is True: A tuple (primals_out, tangents_out, aux) where: - aux: Auxiliary data returned by `fun` """ return backend.linalg.jvp(fun, primals, tangents, has_aux=self.has_aux) def compute_output_spec(self, fun, primals, tangents): # Infer primal output spec if self.has_aux: primals_out_spec, aux_spec = backend.compute_output_spec( fun, *primals ) else: primals_out_spec = backend.compute_output_spec(fun, *primals) # Tangents output should match primals output in structure and shape tangents_out_spec = tree.map_structure( lambda x: KerasTensor(x.shape, x.dtype), primals_out_spec ) if self.has_aux: return primals_out_spec, tangents_out_spec, aux_spec return primals_out_spec, tangents_out_spec @keras_export(["keras.ops.jvp", "keras.ops.linalg.jvp"]) def jvp(fun, primals, tangents, has_aux=False): """Computes a (forward-mode) Jacobian-vector product of `fun`. Args: fun: Function to be differentiated. Its arguments should be arrays, scalars, or standard Python containers of arrays or scalars. It should return an array, scalar, or standard Python container of arrays or scalars. primals: The primal values at which the Jacobian of `fun` should be evaluated. Should be either a tuple or a list of arguments, and its length should be equal to the number of positional parameters of `fun`. tangents: The tangent vector for which the Jacobian-vector product should be evaluated. Should be either a tuple or a list of tangents, with the same tree structure and array shapes as `primals`. has_aux: Optional, bool. Indicates whether `fun` returns a pair where the first element is considered the output of the mathematical function to be differentiated and the second element is auxiliary data. Default is False. Returns: If `has_aux` is False, returns a (`primals_out`, `tangents_out`) pair, where `primals_out` is `fun(*primals)`, and `tangents_out` is the Jacobian-vector product of `fun` evaluated at `primals` with `tangents`. The `tangents_out` value has the same Python tree structure and shapes as `primals_out`. If `has_aux` is True, returns a (`primals_out`, `tangents_out`, `aux`) tuple where `aux` is the auxiliary data returned by `fun`. Example: >>> from keras import ops >>> a1, a2 = ops.convert_to_tensor(0.1), ops.convert_to_tensor(0.2) >>> primals, tangents = ops.jvp(ops.sin, (a1,), (a2,)) >>> primals 0.09983342 >>> tangents 0.19900084 """ if any_symbolic_tensors((primals, tangents)): return JVP(has_aux=has_aux).symbolic_call(fun, primals, tangents) return backend.linalg.jvp(fun, primals, tangents, has_aux=has_aux)