<%@include file="includes/setup.md.rsp"%>

<%@string fcnname="product"%>
<% fcnname <- "<%@string name="fcnname"%>" %>
<%@meta title="${fcnname}() benchmarks"%>
<%@meta author="Henrik Bengtsson"%>
<%@meta date="2014-06-04"%>

<%@include file="${header}"%>


# <%@meta name="title"%>

This report benchmark the performance of <%=fcnname%>() against alternative methods.

## Alternative methods

* product_R()
* prod()

where

```r
<%=withCapture({
product_R <- function(x, na.rm = FALSE, ...) {
  # Nothing todo?
  if (length(x) == 0L) return(0);

  # Any missing values?
  if (na.rm) {
    x <- x[!is.na(x)];
  }

  # Any zeros?
  if (is.integer(x) && any(x == 0)) return(0);

  # Calculate product via logarithmic sum
  sign <- if (sum(x < 0) %% 2 == 0) +1 else -1;
  x <- abs(x);
  x <- log(x);
  x <- sum(x, na.rm = FALSE);
  x <- exp(x);
  y <- sign*x;

  y;
} # product_R()
})%>
```


## Data
```r
<%=withCapture({
<%@include file="R/random-vectors.R"%>
data <- rvectors(mode = "double")
data <- data[1:4]
})%>
```

## Results

<% for (ii in seq_along(data)) { %>
<%
dataLabel <- names(data)[ii]
message(dataLabel)
x <- data[[dataLabel]]
gc()
%>
### <%=dataLabel%> vector

```r
<%=withCapture({
x <- data[[.dataLabel.]]
gc()

stats <- microbenchmark(
 product   = product(x, na.rm = FALSE),
 product_R = product_R(x, na.rm = FALSE),
 prod      = prod(x, na.rm = FALSE),
 unit = "ms"
)
})%>
```

<% benchmarkResults(stats, tags=dataLabel) %>

<% } # for (ii ...) %>


<%@include file="${footer}"%>


<%---------------------------------------------------------------------------
HISTORY:
2014-06-02
o Created.
---------------------------------------------------------------------------%>
