2. Efficient visPedigree Workflows

This vignette summarizes efficient day-to-day workflows for visPedigree after the tidyped architecture updates. The goal is simple:

tidy once,
reuse the resulting tidyped object many times,
subset safely,
trace candidates explicitly when pedigree completeness matters.

For basic tidying, see tidy-pedigree. For downstream statistics, see pedigree-analysis.

1. Load packages and example data

library(visPedigree)
library(data.table)

data(simple_ped, package = "visPedigree")

2. Tidy once, reuse many times

The most efficient workflow is to create a master tidyped object once and reuse it for plotting, tracing, inbreeding, and matrix calculations.

tp_master <- tidyped(simple_ped)

class(tp_master)
#> [1] "tidyped"    "data.table" "data.frame"
is_tidyped(tp_master)
#> [1] TRUE
pedmeta(tp_master)
#> $selfing
#> [1] FALSE
#> 
#> $bisexual_parents
#> character(0)
#> 
#> $genmethod
#> [1] "top"

This avoids repeated validation, founder insertion, loop checking, generation assignment, and integer re-indexing.

3. Fast repeated tracing from an existing `tidyped`

When the input is already a tidyped object and cand is supplied, tidyped() now uses a fast path. It skips the expensive global preprocessing steps and directly traces the requested candidates.

tp_up <- tidyped(tp_master, cand = "J5X804", trace = "up", tracegen = 2)
tp_down <- tidyped(tp_master, cand = "J0Z990", trace = "down")

has_candidates(tp_up)
#> [1] TRUE
tp_up[, .(Ind, Sire, Dam, Cand)]
#> Tidy Pedigree Object
#>       Ind   Sire    Dam   Cand
#>    <char> <char> <char> <lgcl>
#> 1: J3L886   <NA>   <NA>  FALSE
#> 2: J3X697   <NA>   <NA>  FALSE
#> 3: J3Y620   <NA>   <NA>  FALSE
#> 4: J3Y771   <NA>   <NA>  FALSE
#> 5: J4E185 J3L886 J3X697  FALSE
#> 6: J4Y326 J3Y620 J3Y771  FALSE
#> 7: J5X804 J4Y326 J4E185   TRUE

Recommended pattern:

# expensive once
# tp_master <- tidyped(raw_ped)

# cheap many times
# tp_a <- tidyped(tp_master, cand = ids_a, trace = "up")
# tp_b <- tidyped(tp_master, cand = ids_b, trace = "all", tracegen = 3)
# tp_c <- tidyped(tp_master, cand = ids_c, trace = "down")

4. Safe `data.table` usage on `tidyped`

A tidyped object is also a data.table, so by-reference workflows remain available.

4.1 Adding new columns is safe

tp_work <- copy(tp_master)
tp_work[, phenotype := seq_len(.N)]

class(tp_work)
#> [1] "tidyped"    "data.table" "data.frame"
head(tp_work[, .(Ind, phenotype)])
#>       Ind phenotype
#>    <char>     <int>
#> 1: J0C032         1
#> 2: J0C185         2
#> 3: J0C231         3
#> 4: J0C317         4
#> 5: J0C355         5
#> 6: J0C450         6

The tidyped class is preserved after := operations.

4.2 Incomplete row subsetting now degrades safely

If row filtering removes required parents, the result is no longer a complete pedigree. In that case the object is downgraded to a plain data.table with a warning.

ped_year <- data.table(
  Ind = c("A", "B", "C", "D"),
  Sire = c(NA, NA, "A", "C"),
  Dam = c(NA, NA, "B", "B"),
  Year = c(2000, 2000, 2005, 2006)
)

tp_year <- tidyped(ped_year)
sub_dt <- tp_year[Year > 2005]
#> Warning: Subsetting removed parent records. Result is a plain data.table, not a tidyped.
#> Use tidyped(tp, cand = ids, trace = "up") to extract a valid sub-pedigree.

class(sub_dt)
#> [1] "data.table" "data.frame"
sub_dt
#>       Ind   Sire    Dam  Year Family FamilySize   Gen    Sex IndNum SireNum
#>    <char> <char> <char> <num> <char>      <int> <int> <char>  <int>   <int>
#> 1:      D      C      B  2006    CxB          1     3   <NA>      4       3
#>    DamNum
#>     <int>
#> 1:      2

This behavior prevents invalid integer pedigree indices from silently reaching C++ code.

Completeness-sensitive analyses now fail fast on such truncated subsets:

inbreed(sub_dt)
#> Error:
#> ! inbreed() requires a structurally complete pedigree. This input appears to be a row-truncated subset with missing parent records.
#> Compute on the full pedigree first, or extract a valid sub-pedigree with `tidyped(tp, cand = ids, trace = "up")`.

4.3 Use explicit tracing when you need a valid sub-pedigree

If the goal is to keep a structurally valid pedigree around focal individuals, use candidate tracing instead of ad hoc row filtering.

valid_sub_tp <- tidyped(tp_year, cand = "D", trace = "up")

class(valid_sub_tp)
#> [1] "tidyped"    "data.table" "data.frame"
valid_sub_tp[, .(Ind, Sire, Dam, Cand)]
#> Tidy Pedigree Object
#>       Ind   Sire    Dam   Cand
#>    <char> <char> <char> <lgcl>
#> 1:      A   <NA>   <NA>  FALSE
#> 2:      B   <NA>   <NA>  FALSE
#> 3:      C      A      B  FALSE
#> 4:      D      C      B   TRUE

Then compute on the valid sub-pedigree and, if needed, filter the final result back to the focal individuals:

inbreed(valid_sub_tp)[Ind == "D", .(Ind, f)]
#>       Ind     f
#>    <char> <num>
#> 1:      D  0.25

5. `splitped()` versus `pedsubpop()`

These two functions serve different purposes.

splitped() returns the actual split pedigree objects.
pedsubpop() returns a summary table.

sub_tps <- splitped(tp_master)
length(sub_tps)
#> [1] 2
class(sub_tps[[1]])
#> [1] "tidyped"    "data.table" "data.frame"

pedsubpop(tp_master)
#>     Group     N N_Sire N_Dam N_Founder
#>    <char> <int>  <int> <int>     <int>
#> 1:    GP1    56     27    27        26
#> 2:    GP2     3      1     1         2

Use splitped() when you need downstream analysis on each component. Use pedsubpop() when you only need the component summary.

6. Use accessors instead of manual attribute checks

The updated accessors are the preferred way to inspect object state.

tp_f <- inbreed(tp_master)

is_tidyped(tp_f)
#> [1] TRUE
has_inbreeding(tp_f)
#> [1] TRUE
has_candidates(tp_f)
#> [1] FALSE
pedmeta(tp_f)
#> $selfing
#> [1] FALSE
#> 
#> $bisexual_parents
#> character(0)
#> 
#> $genmethod
#> [1] "top"

This is preferable to hand-written checks such as "f" %in% names(tp) or manual attribute access scattered throughout user code.

7. Recommended high-efficiency workflow

A practical pattern for large pedigrees is:

# 1. build one validated master object
# tp_master <- tidyped(raw_ped)

# 2. add analysis-specific columns in place
# tp_master[, phenotype := pheno_vector]
# tp_master[, cohort := year_vector]

# 3. extract valid candidate sub-pedigrees explicitly
# tp_sel <- tidyped(tp_master, cand = selected_ids, trace = "up", tracegen = 3)

# 4. run downstream analysis on either the full master or traced sub-pedigree
# pedstats(tp_master)
# pedmat(tp_sel)
# inbreed(tp_sel)
# visped(tp_sel)

# 5. split only when disconnected components really matter
# comps <- splitped(tp_master)

8. Practical rules of thumb

Call tidyped() on raw pedigree data once.
Reuse the resulting tidyped object as the master pedigree.
Use tidyped(tp_master, cand = ...) for valid local extraction.
Use ordinary row filtering only when a plain data.table result is acceptable.
Use splitped() for actual component objects and pedsubpop() for summaries.
Use pedmeta(), is_tidyped(), has_inbreeding(), and has_candidates() to inspect object state.

These rules keep workflows fast, explicit, and structurally safe.