get_HDF5_colSds

C++ Function Reference

1 Signature

Eigen::VectorXd BigDataStatMeth::get_HDF5_colSds(BigDataStatMeth::hdf5Dataset *dsA, bool bparal, Rcpp::Nullable< int > wsize, Rcpp::Nullable< int > threads)

2 Description

Column standard deviations of an HDF5 matrix (block-wise, parallel).

3 Parameters

dsA (BigDataStatMeth::hdf5Dataset *): Open HDF5 dataset.
bparal (bool): Enable OpenMP parallelism.
wsize (Rcpp::Nullable< int >): Block size (NULL = auto).
threads (Rcpp::Nullable< int >): Thread count (NULL = auto).

4 Returns

Vector of length ncols_R.

5 Details

Equivalent to apply(X, 2, sd) — uses Bessel’s correction (n-1).

6 Call Graph

7 Source Code

Implementation

File: inst/include/hdf5Algebra/matrixAggregations.hpp • Lines 480-491

inline Eigen::VectorXd get_HDF5_colSds(BigDataStatMeth::hdf5Dataset* dsA,
                                        bool bparal,
                                        Rcpp::Nullable<int> wsize,
                                        Rcpp::Nullable<int> threads)
{
    try {
        return get_HDF5_colVars(dsA, bparal, wsize, threads).array().sqrt();
    } catch (std::exception& e) {
        throw std::runtime_error(std::string("c++ exception get_HDF5_colSds: ")
                                 + e.what());
    }
}

8 Usage Example

#include "BigDataStatMeth.hpp"

// Example usage
auto result = get_HDF5_colSds(...);

---
title: "get_HDF5_colSds"
subtitle: "C++ Function Reference"
---

## Signature

```cpp
Eigen::VectorXd BigDataStatMeth::get_HDF5_colSds(BigDataStatMeth::hdf5Dataset *dsA, bool bparal, Rcpp::Nullable< int > wsize, Rcpp::Nullable< int > threads)
```

## Description

Column standard deviations of an HDF5 matrix (block-wise, parallel).

## Parameters

- `dsA` (`BigDataStatMeth::hdf5Dataset *`): Open HDF5 dataset.
- `bparal` (`bool`): Enable OpenMP parallelism.
- `wsize` (`Rcpp::Nullable< int >`): Block size (NULL = auto).
- `threads` (`Rcpp::Nullable< int >`): Thread count (NULL = auto).

## Returns

Vector of length ncols_R.

## Details

Equivalent to apply(X, 2, sd) — uses Bessel's correction (n-1).

## Call Graph

::: {.diagram-section}
<object type="image/svg+xml" data="images/namespace_big_data_stat_meth_a7e94ee156abe0c78618aca6a57b0e70a_cgraph.svg" class="class-diagram">
  <img src="images/namespace_big_data_stat_meth_a7e94ee156abe0c78618aca6a57b0e70a_cgraph.svg" alt="Function dependencies"/>
</object>
:::

## Source Code

::: {.callout-note collapse="true"}
### Implementation

**File:** `inst/include/hdf5Algebra/matrixAggregations.hpp` • **Lines 480-491**

```cpp
inline Eigen::VectorXd get_HDF5_colSds(BigDataStatMeth::hdf5Dataset* dsA,
                                        bool bparal,
                                        Rcpp::Nullable<int> wsize,
                                        Rcpp::Nullable<int> threads)
{
    try {
        return get_HDF5_colVars(dsA, bparal, wsize, threads).array().sqrt();
    } catch (std::exception& e) {
        throw std::runtime_error(std::string("c++ exception get_HDF5_colSds: ")
                                 + e.what());
    }
}
```
:::

## Usage Example

```cpp
#include "BigDataStatMeth.hpp"

// Example usage
auto result = get_HDF5_colSds(...);
```