spmap: Map Functions Over Glycan Structure Vectors and Multiple...

In glyrepr: Representation for Glycan Compositions and Structures

Map Functions Over Glycan Structure Vectors and Multiple Arguments

Description

These functions apply a function to each unique structure in a glycan structure vector along with corresponding elements from multiple other vectors, taking advantage of hash-based deduplication to avoid redundant computation. Similar to purrr pmap functions, but optimized for glycan structure vectors.

Usage

spmap(.l, .f, ...)

spmap_vec(.l, .f, ..., .ptype = NULL)

spmap_lgl(.l, .f, ...)

spmap_int(.l, .f, ...)

spmap_dbl(.l, .f, ...)

spmap_chr(.l, .f, ...)

spmap_structure(.l, .f, ...)

Arguments

.l	A list where the first element is a glycan structure vector (glyrepr_structure) and the remaining elements are vectors of the same length or length 1 (will be recycled).
.f	A function that takes an igraph object (from first element of .l) and values from other elements, returning a result. Can be a function, purrr-style lambda (~ .x + .y + .z), or a character string naming a function. A structure with floating metadata is passed as one annotated graph.
...	Additional arguments passed to .f.
.ptype	A prototype for the return type (for spmap_vec).

Details

These functions only compute .f once for each unique combination of structure and corresponding values from other vectors, then map the results back to the original vector positions.

spmap_structure() reuses unchanged graphs and validates and canonicalizes changed graphs returned by .f. A callback that changes vertex identities or components of a floating structure must also update its floating_parts and floating_substituents metadata.

NA Handling: NA elements in the first argument (glycan structure vector) are preserved in the output.

Time Complexity Performance:

Performance scales with unique combinations of all arguments rather than total vector length. When argument vectors are highly redundant, performance approaches O(unique_structures). Scaling factor shows time increase when vector size increases 20x.

Return Types:

• spmap(): Returns a list with the same length as the input vectors

• spmap_vec(): Returns an atomic vector with the same length as the input vectors

• spmap_lgl(): Returns a logical vector

• spmap_int(): Returns an integer vector

• spmap_dbl(): Returns a double vector

• spmap_chr(): Returns a character vector

• spmap_structure(): Returns a new glycan structure vector (.f must return igraph objects)

Value

• spmap(): A list

• spmap_vec(): An atomic vector of type specified by .ptype

• spmap_lgl/int/dbl/chr(): Atomic vectors of the corresponding type

• spmap_structure(): A new glyrepr_structure object

Examples

# Create structure vectors with duplicates
core1 <- o_glycan_core_1()
core2 <- n_glycan_core()
structures <- c(core1, core2, core1)  # core1 appears twice
weights <- c(1.0, 2.0, 1.0)  # corresponding weights
factors <- c(2, 3, 2)  # corresponding factors

# Map a function that uses structure, weight, and factor
spmap_dbl(list(structures, weights, factors),
          function(g, w, f) igraph::vcount(g) * w * f)

# Use purrr-style lambda functions
spmap_dbl(list(structures, weights, factors), ~ igraph::vcount(..1) * ..2 * ..3)

# Test with recycling
spmap_dbl(list(structures, 2.0, 3), ~ igraph::vcount(..1) * ..2 * ..3)

glyrepr documentation built on Sept. 22, 2026, 5:09 p.m.