can_allocate

can_allocate

SYSTEM_UTILS

1 Description

Checks whether a given amount of memory can be safely allocated while maintaining a safety margin.

2 Usage

can_allocate(size_gb, safety_margin_pct = 20.0)

3 Arguments

Parameter	Description
`size_gb`	Size in gigabytes (GB) to check
`safety_margin_pct`	Percentage of available RAM to keep free (default 20 percent)

4 Value

Logical. TRUE if allocation is likely safe, FALSE otherwise

5 Details

This function checks if the requested memory can be allocated while keeping a safety margin of free RAM. This helps prevent: - System instability from memory exhaustion - Swapping (which degrades performance) - Out-of-memory errors from other processes

Formula: can_allocate = (size_gb < available_ram * (1 - safety_margin / 100))

Safety margin guidelines:

6 Examples

\donttest{
# Check if 1 GB can be safely allocated
if (can_allocate(1)) {
  message("1 GB allocation is safe")
} else {
  message("Not enough RAM for 1 GB allocation")
}

# Use it to decide how much data to load
fn <- tempfile(fileext = ".h5")
X  <- hdf5_create_matrix(fn, "data/M",
                          data = matrix(rnorm(1000), 100, 10))

size_gb <- prod(dim(X)) * 8 / 1e9   # estimate in GB
if (can_allocate(size_gb)) {
  mat <- as.matrix(X)
} else {
  mat <- X[1:50, ]   # load subset
}

hdf5_close_all()
unlink(fn)
}

7 See Also

get_available_ram

---
title: "can_allocate"
subtitle: "can_allocate"
---

<span class="category-badge system_utils">SYSTEM_UTILS</span>

## Description

Checks whether a given amount of memory can be safely allocated
while maintaining a safety margin.

## Usage

```r
can_allocate(size_gb, safety_margin_pct = 20.0)
```
## Arguments

::: {.param-table}
| Parameter | Description |
|-----------|-------------|
| `size_gb` | Size in gigabytes (GB) to check |
| `safety_margin_pct` | Percentage of available RAM to keep free   (default 20 percent)  |
:::

## Value

::: {.return-value}
Logical. TRUE if allocation is likely safe, FALSE otherwise

:::
## Details

This function checks if the requested memory can be allocated while
keeping a safety margin of free RAM. This helps prevent:
- System instability from memory exhaustion
- Swapping (which degrades performance)
- Out-of-memory errors from other processes

**Formula:**
`can_allocate = (size_gb < available_ram * (1 - safety_margin / 100))`

**Safety margin guidelines:**
\itemize{
  \item 20 percent (default): Conservative, recommended for most cases
  \item 10 percent: Moderate, for controlled environments
  \item 5 percent: Aggressive, only if you know what you're doing
  \item 0 percent: Maximum risk, not recommended
}

## Examples
```{r}
#| eval: false
#| warning: false

\donttest{
# Check if 1 GB can be safely allocated
if (can_allocate(1)) {
  message("1 GB allocation is safe")
} else {
  message("Not enough RAM for 1 GB allocation")
}

# Use it to decide how much data to load
fn <- tempfile(fileext = ".h5")
X  <- hdf5_create_matrix(fn, "data/M",
                          data = matrix(rnorm(1000), 100, 10))

size_gb <- prod(dim(X)) * 8 / 1e9   # estimate in GB
if (can_allocate(size_gb)) {
  mat <- as.matrix(X)
} else {
  mat <- X[1:50, ]   # load subset
}

hdf5_close_all()
unlink(fn)
}

```
## See Also

::: {.see-also}
[get_available_ram](get_available_ram.html)

:::