Sub/Super-Gradient
The (sub/super)-gradient of the expression with respect to each variable.
Matrix expressions are vectorized, so the gradient is a matrix. NA indicates variable values are unknown or outside the domain.
grad(object)
object |
An Expression object. |
A list mapping each variable to a sparse matrix.
x <- Variable(2, name = "x") A <- Variable(2, 2, name = "A") value(x) <- c(-3,4) expr <- p_norm(x, 2) grad(expr) value(A) <- rbind(c(3,-4), c(4,3)) expr <- p_norm(A, 0.5) grad(expr) value(A) <- cbind(c(1,2), c(-1,0)) expr <- abs(A) grad(expr)
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