papi.flops <- function(expr)
{
papi.check.ncounters(3L)
ret <- .Call(papi_flops_on)
if (ret == -1L)
stop("PAPI failed to initialize hardware counters.\nYour platform may not support floating point operation event.\n")
eval(expr)
ret <- .Call(papi_flops_off)
if (is.integer(ret) && ret == -1L)
stop("There was a problem recovering the counter information.")
return( ret )
}
#' flops
#'
#' Measuring floating point operations.
#'
#' This function measures the evaluation of the provided expression, expr, for
#' real time, process time, number of floating point operations, and floating
#' point operation rate. The additional arguments, gcFirst and burnin, can be
#' toggled to better simulate the target context.
#'
#' @param expr
#' A valid R expression to be profiled.
#' @param gcFirst
#' logical; determines if garbage collection should be called
#' before profiling.
#' @param burnin
#' logical; determines if the function should first be evaluated
#' with an empty expression.
#'
#' @return
#' The return is a list consisting of:
#' \tabular{ll}{
#' \code{real_time} \tab real time spent evaluating expression \cr
#' \code{proc_time} \tab total process time spent evaluating expression \cr
#' \code{flpops} \tab FLoating Point OPerationS (count) \cr
#' \code{mflops} \tab Mflops (flpops per second) \cr
#' }
#'
#' @keywords programming
#'
#' @examples
#' \dontrun{
#' library(pbdPAPI)
#'
#' system.flops(1+1)
#' }
#'
#' @export
system.flops <- function(expr, gcFirst=TRUE, burnin=TRUE)
{
if (burnin)
b <- system.flops(gcFirst=gcFirst, burnin=FALSE)
if (gcFirst)
invisible(gc(FALSE))
if (missing(expr))
expr <- NULL
events <- c("PAPI_FP_OPS", "PAPI_TOT_CYC")
papi.avail.lookup(events=events, shorthand=FALSE)
ret <- papi.flops(expr=expr)
if (burnin)
{
for (i in 3:length(ret))
ret[[i]] <- max(ret[[i]] - b[[i]], 0)
}
# Store expression call for plotting
attr(ret, "call") <- as.character(match.call()[2])
class(ret) <- c("papi_output", "papi_flops")
return( ret )
}
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