NEWS.md

cgraph 6.0.2

New Features:

• The gradients supplied to argument grads of function cg_function can now also be matched by name (instead of positionally). The names associated with the gradients must match the non-constant arguments of the function provided to argument def.

cgraph 6.0.1

New Features:

• Added operator cg_rowmeans and cg_colmeans.

Bug Fixes:

• Global symbols in the C-API are now correctly defined (fixes CRAN gcc10 error).
• Evaluating or differentiating a graph with operators having invalid inputs or invalid gradient functions no longer causes a segfault.

cgraph 6.0.0

New Features:

• Added operator cg_length, cg_dim, cg_nrow, and cg_ncol.
• Added function cg_graph_get to retrieve a node by name from a graph.
• Nodes can now be subsetted at run-time. Subsetting can be performed by calling the new operators cg_subset1 or cg_subset2, or the corresponding overloaded S3 methods [ and [[ respectively, on a cg_node object.
• Function cg_graph has a new argument eager which can be used to enable or disable eager evaluation. Eager evaluation can also be enabled or disabled on an existing graph by changing data member eager of a cg_graph object.
• Function cg_graph_forward and cg_graph_backward now allow argument target to be the name of the target node, in which case a linear search is performed to retrieve the node by name from the graph prior to a forward or backward pass. Please note that this search can be expensive for large graphs.

Comments:

• The name of a node no longer has to be unique.
• Function cg_graph_run and cg_graph_gradients have been removed.
• Data member nodes of a cgraph object is no longer named for performance reasons. Use function cg_graph_get to retrieve a node by name.
• The performance of function cg_operator has significantly improved. Graphs can now be build considerbly faster.

cgraph 5.0.1

Bug Fixes:

• Fixed a bug in function cg_graph_backward which sometimes caused a computational graph to be traversed in an incorrect order and compute incorrect gradients.

cgraph 5.0.0

New Features:

• Added operator cg_square.
• Operators are now evaluated eagerly. This means that, when an operator is added to a computational graph, it is immediately evaluated (if possible). Eager evaluation makes it easier to debug a computational graph and enables the user to change its control flow at run-time.
• Added function cg_graph_forward and cg_graph_backward to perform a forward pass and backward pass respectively. These functions are similar to function cg_graph_run and cg_graph_gradients but do not use environments to store the values and derivatives of nodes. Instead, the value and derivative of a node are stored 'locally' at each node and can be retrieved by data member value and grad respectively.

Comments:

• Function cg_graph_run and cg_graph_gradients are deprecated and will be removed in the next major release. Use function cg_graph_forward and cg_graph_backward to perform a forward pass and backward pass instead.

Bug Fixes:

• Fixed several memory leaks and protection bugs.

cgraph 4.0.3

Bug Fixes:

• Fixed several protection bugs in the C-API thanks to rchk.

cgraph 4.0.2

New Features:

• Argument index of function cg_graph_gradients can now also be NULL, in which case the nodes in a graph are differented element-wise. This is now also the default behavior.

Comments:

• The default name of a node is now v followed by the node id.
• The S3 classes of the node types (i.e. constant, parameter, input, and operator) are removed for performance reasons. The type of a node can now be retrieved by data member type of a cg_node object.

Bug Fixes:

• Fixed memory leak in function cg_graph_run and cg_graph_gradients.
• Function bsum now prints a correct error message when argument block_size is not a numerical scalar.

cgraph 4.0.1

Bug Fixes:

• Fixed an bug that caused an error when installing cgraph on R versions before 3.5.
• Function cg_session_set_graph no longer prints NULL to the console when the active graph is changed.
• Operator cg_sigmoid now works correctly when argument x is a logical or integer vector or array.

cgraph 4.0.0

Comments:

• The C-API has been completely reworked.
• Operators cg_reshape, !, ==, !=, <, >, <=, and >= are removed.
• R6 class cgraph is removed. Use function cg_graph to create a new graph. The active graph can now be retrieved and changed by function cg_session_graph and cg_session_set_graph respectively.
• Function const, input, parm, and opr have been renamed to cg_constant, cg_input, cg_parameter, and cg_operator respectively.
• Function val and set are removed. The value of a constant or parameter can now be retrieved or changed by data member value of a cg_node object.
• Function run and gradients have been renamed to cg_graph_run and cg_graph_gradients respectively.

New Features:

• The function that is called by an operator is no longer stored as a symbol in the environment of the operator. Instead, each function now has its own global cg_function object which can be linked to an operator. This significantly reduces the size of a cg_graph object.

Bug Fixes:

• Fixed a bug that caused a node to be evaluated to its corresponding cg_node environment rather than its value when calling cg_graph_run and cg_graph_gradients.
• Fixed a bug that caused a segfault when calling function cg_graph_run and cg_graph_gradients on a cg_graph object which contains nodes with an invalid id.

cgraph 3.0.1

Bug Fixes:

• Fixed a bug that caused overloaded S3 methods called by operators to dispatch incorrectly on R versions before 3.5.

cgraph 3.0.0

Comments:

• Large parts of the C-API have been reworked.
• Some naming conventions have changed. Individual names in the name of a function are now separated with an underscore (_) instead of a dot (.). For example, operator cg.matmul is now named cg_matmul. The same rule applies to class names. For example, class cg.node is now named cg_node.
• Function name is removed. Names for nodes are now generated internally in the C-API.
• Function approx.gradients is no longer exported but still avaiable in the package namespace. Please note that this function is not well-optimized and should only be used for testing purposes.
• Calling print on a cg_node object no longer prints the value of the node. Use function val to evaluate a node.

New Features:

• The initialization method of a cgraph object has a new argument library which can be used to specify the function library that is used by the graph.
• The calls of functions and their corresponding gradient functions are now build at run-time.
• Added function val and set to retrieve or set the value of a node respectively.
• A node can now also be named 'grad'. 'grad' is no longer a reserved word.
• Operator cg_mean now calls the base mean function.
• Operator cg_crossprod and cg_tcrossprod now allow argument y to be missing (similarly as the corresponding base functions).
• Argument dim of operator cg_reshape now expects an cg_node object instead of an integer scalar or vector that holds the new array dimensions.

Bug Fixes:

• Fixed a bug that caused a segfault when using cgraph in RStudio on Red Hat Enterprise Linux.

cgraph 2.0.3

Comments:

• The S3 overloaded methods of prefix operators have been marked as deprecated and will be removed in the next major release. Only infix operators like + or - will have S3 overloaded methods.

Bug Fixes:

• Operator sigmoid now correctly handles numerical underflow.
• Operator cg.pmax and cg.pmin are now correctly differentiated when argument x and y are arrays.

New Features:

• Added logical operators !, ==, !=, <, >, <=, and >=.

cgraph 2.0.2

Bug Fixes:

• Nodes that are given a value upon creation are now properly printed to the R console.
• Function run, gradients, and approx.grad no longer cause an infinite loop when member values of a cgraph object is supplied to the values argument of the functions.
• Fixed protection bug in function gradients which caused the R session to crash unexpectedly.
• Function approx.grad now checks whether node x and y evaluate to a numeric vector or array.
• Function approx.grad no longer changes the parent environment of argument values when the argument is an environment.

cgraph 2.0.1

Bug Fixes:

• Function run and gradients no longer change the parent environment of argument values when the argument is an environment.
• Function name no longer generates a name that indicates the node type for performance reasons. Instead, it simply generates the name 'node' followed by the number of nodes that have been added to the graph.
• Fixed several protection bugs in the C-API thanks to rchk.

cgraph 2.0.0

Comments:

• The license of the package has changed from GPL-3 to Apache License 2.0.

New Features:

• Added hyperbolic trigonometry operations sinh and cosh.
• Added inverse hyperbolic trigonometry operations asinh and acosh.
• Data member nodes of a cgraph object is now named to allow more convenient access to the symbols of the nodes in a graph.
• You can now instruct the active graph to no longer automatically evaluate a node when it is printed to the console by setting options(cg.autorun = FALSE).

Bug Fixes:

• An error is now raised when an invalid object is provided to the methods of a cgraph object instead of coercing the object to a valid object.
• Function opr now ignores argument grads when its elements are not properly named.
• Function run now checks whether each node evaluates to a numeric vector or array.
• Function gradients now checks whether the node supplied to argument name evaluates to a numeric vector or array.
• Function get.parms and add.parms now correctly call the underlying C-API.

cgraph 1.0.1

Comments:

• CRAN Review on the cgraph 1.0.0 submission.

cgraph 1.0.0

Comments:

• Initial CRAN Submission.