lazyNumbers (version 1.2.1)

lazyResolve: Resolve lazy numbers

Description

Resolve the lazy numbers in a lazy vector or a lazy matrix; see details.

Usage

lazyResolve(x)

Value

Invisibly returns the lazy vector or matrix x, resolved.

Arguments

x

a lazyVector object or a lazyMatrix object

Details

When an operation between lazy numbers is performed, the resulting lazy number is not the result of the operation, it is the unevaluated operation (wherefrom the word "lazy"). This function performs the evaluation of the operations contained in the lazy numbers of the vector/matrix; the returned lazy vector/matrix has the same values as the input lazy vector/matrix. Applying this function can help to avoid a stack overflow.

Examples

library(lazyNumbers)
n <- 500
p <- seq(1, n, by = 1)
q <- seq(3, 2*n + 1, by = 2)
# fast, because the operations are not evaluated:
x1 <- 2 * (1 + sum(cumprod(lazynb(p) / lazynb(q))))
x2 <- 2 * (1 + sum(cumprod(lazynb(p) / lazynb(q))))
x3 <- 2 * (1 + sum(cumprod(lazynb(p) / lazynb(q))))
# slow, because this evaluates the operations:
lazyResolve(x1)
# fast, because `x1` is resolved now:
as.double(x1)
# slow, because `x2` must be resolved:
as.double(x2)
# fast, because the call to `as.double` has resolved `x2`
as.double(x2)
# slow, because `x3` is not resolved:
x1 == x3
# fast, because `x3` has been resolved by the equality test:
as.double(x3)