Creates a new value node in the computational graph with automatic
differentiation. Input is converted to matrix representation internally.
Arguments
- data
Numeric value (scalar, vector, or matrix)
- label
Optional character label for debugging
Details
All values are stored as matrices internally:
val(5) creates a 1x1 matrix
val(c(1,2,3)) creates a 3x1 column vector
val(matrix(...)) preserves matrix dimensions