Elliott rules

Generated. This page is rendered from indicator::elliott::rule_catalog() by tests/structure_catalog_doc.rs, so it always matches the code of this version. The same catalogue is bound to the behaviour by tests: every identifier a validator reports is listed here with its sentence, variants and assertion, every entry is reported by at least one test sequence for every variant it names, and every threshold is where the behaviour turns.

The validators of indicator::elliott check a given labeling; they do not count waves. A rule makes a labeling invalid and is reported in violations. A guideline is reported in guidelines and leaves valid untouched. The reference for both is the summary of rules and guidelines of Frost and Prechter’s Elliott Wave Principle, read in reproductions; where it leaves a choice open, the choice is this crate’s convention and is marked as such below.

The pivot sequence

Every validator first requires a pivot sequence. The conditions are tested in this order, each over the whole sequence, and the first that fails is reported: check_* returns the SequenceError naming the node, validate_* returns None. A refused sequence gets no verdict.

Order	SequenceError	kind().id()	Condition
1	NodeCount	node_count	The sequence has a node count the structure accepts
2	NotAlternating	not_alternating	Highs and lows alternate
3	TimeOrder	time_order	No node is earlier than the node before it; equal timestamps are accepted
4	PivotPlacement	pivot_placement	Every high lies above the node before it and every low below it, except the nodes whose placement a rule of the structure reports

Structures

Structure	Function	Nodes	Placement left to a rule	Rules	Guidelines
impulse	check_impulse	6	–	3	0
diagonal	check_diagonal	6	–	2	0
correction	check_correction	4	node 3	3	4
triangle	check_triangle	6	–	9	0
combination	check_combination	8, 12	node 3, 7, 11	those of correction, per segment of four nodes	those of correction

The end of wave C of a correction is not held by the placement condition: a wave C that does not continue past wave B is reported as the violation wave_c_must_extend_past_b instead.

Variants

Listed in the order the assignment tests them; a sequence takes the first variant whose condition holds. An impulse has no variants.

Structure	Variant	Condition
diagonal	contracting	Wave 3 is shorter than wave 1, wave 5 shorter than wave 3 and wave 4 shorter than wave 2
diagonal	expanding	Every other sequence
correction	zigzag	Wave A is asserted to subdivide into five waves, or nothing is asserted and wave B retraces less than 90 percent of wave A
correction	running_flat	Not a zigzag, wave B ends beyond the start of wave A and wave C does not end beyond the end of wave A
correction	expanded_flat	Not a zigzag, wave B retraces more than 105 percent of wave A and wave C ends beyond the end of wave A
correction	flat	Every other sequence that is not a zigzag
triangle	expanding	At least two of waves c, d and e end beyond the end of the wave two before them
triangle	barrier	Not expanding, and the ends of waves b and d lie within the barrier tolerance of each other
triangle	contracting	Every other sequence
combination	double_three	Eight nodes: two corrections W and Y joined by one X wave
combination	triple_three	Twelve nodes: three corrections W, Y and Z joined by two X waves

Rules and guidelines

Listed per structure in the order they are tested and reported. Variants are the variants a result can have when it reports the entry; a variant that is missing cannot depart from it, because the check is not made for it or its definition already satisfies it. Needs assertion marks the two rules that can only fail when the subdivision of wave A is asserted (CorrectionOptions::wave_a); without it they hold by construction. A combination reports the entries of correction for each of its segments.

Structure	Identifier	Kind	Variants	Needs assertion	Origin	Thresholds
impulse	wave2_no_full_retrace	rule	–	–	literature rule	–
impulse	wave3_not_shortest	rule	–	–	literature rule	–
impulse	wave4_no_overlap	rule	–	–	literature rule	–
diagonal	wave2_no_full_retrace	rule	contracting, expanding	–	literature rule	–
diagonal	wave3_not_shortest	rule	expanding	–	literature rule	–
correction	wave_c_must_extend_past_b	rule	zigzag, flat, running_flat	–	crate convention	–
correction	zigzag_b_not_beyond_start_of_a	rule	zigzag	wave_a = five	literature rule	–
correction	flat_b_min_retrace	rule	flat	wave_a = three	literature rule	FLAT_B_MIN_RETRACE
correction	zigzag_b_retrace_bound	guideline	zigzag	–	literature guideline	ZIGZAG_B_TYPICAL_MAX
correction	zigzag_c_ends_beyond_a	guideline	zigzag	–	literature guideline	–
correction	flat_b_retrace_bound	guideline	flat, expanded_flat, running_flat	–	literature guideline	FLAT_B_TYPICAL_MAX
correction	flat_c_ends_beyond_a	guideline	flat	–	literature guideline	–
triangle	triangle_c_not_beyond_a	rule	contracting, barrier	–	literature rule	–
triangle	triangle_d_not_beyond_b	rule	contracting	–	literature rule	–
triangle	triangle_e_not_beyond_c	rule	contracting, barrier	–	literature rule	–
triangle	expanding_triangle_c_beyond_a	rule	expanding	–	literature rule	–
triangle	expanding_triangle_d_beyond_b	rule	expanding	–	literature rule	–
triangle	expanding_triangle_e_beyond_c	rule	expanding	–	literature rule	–
triangle	expanding_triangle_b_retrace	rule	expanding	–	literature rule	EXPANDING_TRIANGLE_RETRACE_MIN, EXPANDING_TRIANGLE_RETRACE_MAX
triangle	expanding_triangle_c_retrace	rule	expanding	–	literature rule	EXPANDING_TRIANGLE_RETRACE_MIN, EXPANDING_TRIANGLE_RETRACE_MAX
triangle	expanding_triangle_d_retrace	rule	expanding	–	literature rule	EXPANDING_TRIANGLE_RETRACE_MIN, EXPANDING_TRIANGLE_RETRACE_MAX

What each entry demands (statement), the sentence reported with its identifier under the default options (detail), and what of it is this crate’s convention:

Structure	Identifier	Statement	Sentence reported	Convention
impulse	wave2_no_full_retrace	Wave 2 never moves beyond the start of wave 1	Wave 2 retraced beyond the start of wave 1	a wave that ends exactly on the level counts as beyond it
impulse	wave3_not_shortest	Wave 3 is never the shortest of waves 1, 3 and 5: it is not shorter than both others	Wave 3 is the shortest of waves 1, 3, and 5	–
impulse	wave4_no_overlap	Wave 4 never moves beyond the end of wave 1	Wave 4 entered wave 1’s price territory	a wave that ends exactly on the level counts as beyond it
diagonal	wave2_no_full_retrace	Wave 2 never moves beyond the start of wave 1	Wave 2 retraced beyond the start of wave 1	taken over from the impulse, and whether the literature states it for diagonals in this form is not established; a wave that ends exactly on the level counts as beyond it
diagonal	wave3_not_shortest	Wave 3 is never the shortest of waves 1, 3 and 5: it is not shorter than both others	Wave 3 is the shortest of waves 1, 3, and 5	taken over from the impulse, and whether the literature states it for diagonals in this form is not established
correction	wave_c_must_extend_past_b	Wave C continues past the end of wave B in wave A’s direction	Wave C did not continue past wave B in wave A’s direction	–
correction	zigzag_b_not_beyond_start_of_a	In a zigzag, wave B never moves beyond the start of wave A	Wave B moved beyond the start of wave A	a wave that ends exactly on the level counts as not beyond it
correction	flat_b_min_retrace	In a flat, wave B retraces at least 90 percent of wave A	Wave B retraced less than 90% of wave A	–
correction	zigzag_b_retrace_bound	A zigzag’s wave B retraces at most 78.6 percent of wave A	Wave B retraced more than a Zigzag’s typical bound (78.6%) without qualifying as a Flat	79 percent is written as 0.786
correction	zigzag_c_ends_beyond_a	A zigzag’s wave C ends beyond the end of wave A	Wave C did not end beyond the end of wave A	a wave that ends exactly on the level counts as not beyond it
correction	flat_b_retrace_bound	A flat’s wave B retraces at most 138.2 percent of wave A, or the bound set as an option	Wave B retraced more than a Flat’s typical bound (138.2%)	138 percent is written as 1.382
correction	flat_c_ends_beyond_a	The wave C of a flat that is neither expanded nor running ends beyond the end of wave A	Wave C did not end beyond the end of wave A	a wave that ends exactly on the level counts as not beyond it
triangle	triangle_c_not_beyond_a	In a contracting or barrier triangle, wave c never moves beyond the end of wave a	Wave C moved beyond the end of wave A	a wave that ends exactly on the level counts as not beyond it
triangle	triangle_d_not_beyond_b	In a contracting triangle, wave d never moves beyond the end of wave b	Wave D moved beyond the end of wave B	a wave that ends exactly on the level counts as not beyond it
triangle	triangle_e_not_beyond_c	In a contracting or barrier triangle, wave e never moves beyond the end of wave c	Wave E moved beyond the end of wave C	a wave that ends exactly on the level counts as not beyond it
triangle	expanding_triangle_c_beyond_a	In an expanding triangle, wave c moves beyond the end of wave a	Wave C did not move beyond the end of wave A	a wave that ends exactly on the level counts as not beyond it
triangle	expanding_triangle_d_beyond_b	In an expanding triangle, wave d moves beyond the end of wave b	Wave D did not move beyond the end of wave B	a wave that ends exactly on the level counts as not beyond it
triangle	expanding_triangle_e_beyond_c	In an expanding triangle, wave e moves beyond the end of wave c	Wave E did not move beyond the end of wave C	a wave that ends exactly on the level counts as not beyond it
triangle	expanding_triangle_b_retrace	In an expanding triangle, wave b retraces at least 100 and at most 150 percent of wave a	Wave B retraced less than 100% or more than 150% of wave A	–
triangle	expanding_triangle_c_retrace	In an expanding triangle, wave c retraces at least 100 and at most 150 percent of wave b	Wave C retraced less than 100% or more than 150% of wave B	–
triangle	expanding_triangle_d_retrace	In an expanding triangle, wave d retraces at least 100 and at most 150 percent of wave c	Wave D retraced less than 100% or more than 150% of wave C	–

The sentence of flat_b_retrace_bound carries its bound, which is an option (CorrectionOptions::flat_b_typical_max), as a percentage.

Thresholds

The public constants of the module and what each decides. A constant with two uses has two rows. EXTENDED_WAVE_MIN_RATIO belongs to the measure identify_extended_wave, not to an entry of the table above.

Constant	Value	Role	Origin	Option	Meaning	Convention
FLAT_B_MIN_RETRACE	0.9	form boundary	crate convention	–	Without an assertion about wave A, a correction whose wave B retraces at least this share of wave A is a flat, below it a zigzag	–
FLAT_B_MIN_RETRACE	0.9	rule	literature rule	–	In a flat, wave B retraces at least this share of wave A	–
EXPANDED_FLAT_B_MIN	1.05	form boundary	literature rule	–	A flat whose wave B retraces more than this share of wave A and whose wave C ends beyond the end of wave A is an expanded flat	–
ZIGZAG_B_TYPICAL_MAX	0.786	guideline	literature guideline	–	A zigzag’s wave B typically retraces at most this share of wave A	79 percent is written as 0.786
FLAT_B_TYPICAL_MAX	1.382	guideline	literature guideline	flat_b_typical_max	A flat’s wave B usually retraces at most this share of wave A	138 percent is written as 1.382
EXPANDING_TRIANGLE_RETRACE_MIN	1	rule	literature rule	–	In an expanding triangle, waves b, c and d each retrace at least this share of the wave before them	–
EXPANDING_TRIANGLE_RETRACE_MAX	1.5	rule	literature rule	–	In an expanding triangle, waves b, c and d each retrace at most this share of the wave before them	–
BARRIER_LEVEL_TOLERANCE	0.05	form boundary	crate convention	barrier_tolerance	A triangle that is not expanding is a barrier triangle if the ends of waves b and d lie at most this share of the length of wave b apart	–
EXTENDED_WAVE_MIN_RATIO	1.618	guideline	crate convention	–	A wave 1, 3 or 5 of an impulse at least this many times as long as the longer of the other two is reported as extended by identify_extended_wave	–

Not among the checks

The checks above are what is reported as a rule or a guideline. identify_extended_wave and is_truncated_fifth are measures of the impulse with their own functions and no identifier, and only the threshold of the former is listed; TriangleValidation::running and DiagonalValidation::wave4_overlaps_wave1 are properties of a result; the asserted DiagonalKind enters no check. Rules of the literature that need the subdivision of a wave or its place in a larger count are not checked, and the documentation of each check_* function names them.

Deriving the flow of the checks

The conditions of the pivot sequence are steps that end the flow when they fail; the rules and guidelines are steps that each report on their own. examples/elliott_check_flow.rs, run with cargo run --example elliott_check_flow:

use kestrel_chartkit::indicator::elliott::{rule_catalog, CheckEntry};

/// The variants a check can be reported for, or `all` for a structure without variants.
fn applies_to(check: &CheckEntry) -> String {
    if check.variants.is_empty() {
        return "all".to_string();
    }
    let ids: Vec<&str> = check.variants.iter().map(|variant| variant.id()).collect();
    ids.join(", ")
}

fn main() {
    let catalog = rule_catalog();
    for entry in catalog.structures {
        let counts: Vec<String> = entry.node_counts.iter().map(usize::to_string).collect();
        println!(
            "flow {} ({} nodes)",
            entry.structure.id(),
            counts.join(" or ")
        );

        // First the pivot sequence. The conditions are tested in this order, and the first one
        // that fails ends the flow: the sequence is refused, there is no verdict.
        for condition in catalog.sequence_conditions {
            println!("  step {}: {}", condition.error.id(), condition.text);
            println!("    fails -> refused ({})", condition.error.id());
        }

        // Then the variant: the first whose condition holds.
        for variant in entry.variants {
            println!("  variant {}: {}", variant.variant.id(), variant.text);
        }

        // Then every rule and guideline of the variant. None ends the flow: each one that fails
        // is reported, a rule as a violation, a guideline as a deviation.
        for check in entry.rules.iter().chain(entry.guidelines) {
            println!(
                "  step {} [{}]: {}",
                check.id,
                applies_to(check),
                check.statement
            );
            println!("    fails -> {} \"{}\"", check.kind.id(), check.detail);
        }
    }
}