# Crate transpose[−][src]

Utility for transposing multi-dimensional data stored as a flat slice

This library treats Rust slices as flattened row-major 2D arrays, and provides functions to transpose these 2D arrays, so that the row data becomes the column data, and vice versa.

// Create a 2D array in row-major order: the rows of our 2D array are contiguous, // and the columns are strided let input_array = vec![ 1, 2, 3, 4, 5, 6]; // Treat our 6-element array as a 2D 3x2 array, and transpose it to a 2x3 array let mut output_array = vec![0; 6]; transpose::transpose(&input_array, &mut output_array, 3, 2); // The rows have become the columns, and the columns have become the rows let expected_array = vec![ 1, 4, 2, 5, 3, 6]; assert_eq!(output_array, expected_array); // If we transpose our data again, we should get our original data back. let mut final_array = vec![0; 6]; transpose::transpose(&output_array, &mut final_array, 2, 3); assert_eq!(final_array, input_array);

This library supports both in-place and out-of-place transposes. The out-of-place transpose is much, much faster than the in-place transpose – the in-place transpose should only be used in situations where the system doesn’t have enough memory to do an out-of-place transpose.

The out-of-place transpose uses one out of three different algorithms depending on the length of the input array.

- Small: simple iteration over the array.
- Medium: divide the array into tiles of fixed size, and process each tile separately.
- Large: recursively split the array into smaller parts until each part is of a good size for the tiling algorithm, and then transpose each part.

## Functions

transpose | Transpose the input array into the output array. |

transpose_inplace | Transpose the input array in-place. |