Description
Generate bounded signed changes with cumulative opening/closing reconciliation and explicit subtotal bars.
A chart dataset contains values plus the labels, grouping, totals, or missing-value conventions needed to interpret them. Separating the numeric construction from plotting makes conservation rules and deliberate edge cases visible before a chart is rendered.
Generate bounded signed changes with cumulative opening/closing reconciliation and explicit subtotal bars.
When to use this tool
Use this generator to create reproducible waterfall change dataset cases from the supplied model or bank. Inspect the returned evidence before using cases in a test or exercise.
How to use the tool and how it works
- Supply opening, minimumChange, maximumChange, count, subtotalAfter in the field shapes below. Set seed when you need an explicit replay.
- Run the tool and correct any input error. For generated controls, distinguish a successful fixture containing an invalid case from failure to generate the fixture.
- Read changes, closing, bars. Use the conventions below and keep answer-bearing fields separate when presenting an exercise.
Draw signed integer changes, check every cumulative total using exact integer arithmetic, and delegate cumulative sums beginning at opening. Emit one from/to change bar per draw and zero-based subtotal bars after the requested one-based change positions.1
Delegated operations used for this result: cumulative sum. Their calculation or parsing conventions apply to the corresponding result fields.2
| Input field | Meaning and units | Accepted input |
|---|---|---|
| opening | Opening | Required. Safe integer. |
| minimumChange | Minimum Change | Required. Safe integer. |
| maximumChange | Maximum Change | Required. Safe integer. |
| count | Requested count; the mechanics explain whether one draw expands into several returned records. | Required. Safe integer; minimum 1; maximum 32. |
| subtotalAfter | Subtotal After | Required. Array of Safe integer; minimum 1; maximum 32.; minimum items 0; maximum items 32. |
| seed | Optional numeric seed; takes precedence over context randomness. Without either, use the fixed tool.io default seed. | Optional. Safe integer. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| changes | Changes | Required. Array of Safe integer.; minimum items 1; maximum items 32. |
| closing | Closing | Required. Safe integer. |
| bars | Bars | Required. Array of Object; no unknown keys.; minimum items 1; maximum items 64. |
| bars[].kind | Kind | Required. Text; one of "change", "subtotal". |
| bars[].after | After | Required. Safe integer. |
| bars[].from | From | Required. Safe integer. |
| bars[].to | To | Required. Safe integer. |
| randomness | Replay metadata: source is seed or context; seed is the normalized 32-bit seed or null for a context source. | Required. Object; no unknown keys. |
| randomness.seed | Optional numeric replay seed; normalization and precedence are explained below. | Required. Safe integer. or Null. |
| randomness.source | Source | Required. Text; one of "context", "seed". |
An explicit safe-integer seed takes precedence over injected context randomness and is normalized to an unsigned 32-bit integer. With no seed and no context source, replay uses the fixed tool.io default seed. A context source must return finite values from zero inclusive to one exclusive; its advancing state must be retained separately. randomness records the source and normalized seed, or null for context. These generators are not cryptographic random sources.
{
"input": {
"opening": 10,
"minimumChange": -2,
"maximumChange": 3,
"count": 2,
"subtotalAfter": [
2
],
"seed": 42
},
"output": {
"changes": [
1,
0
],
"closing": 11,
"bars": [
{
"kind": "change",
"after": 1,
"from": 10,
"to": 11
},
{
"kind": "change",
"after": 2,
"from": 11,
"to": 11
},
{
"kind": "subtotal",
"after": 2,
"from": 0,
"to": 11
}
],
"randomness": {
"seed": 42,
"source": "seed"
}
}
}Limitations and assumptions
- Subtotal positions are distinct and cannot exceed the change count. Values share a caller-chosen numeric scale and have no implied financial meaning; chart geometry and formatting remain with the renderer.
- A replay requires the same complete input and implementation. Randomized construction does not guarantee uniform coverage of every feasible output; finite samples can repeat unless a distinct-selection rule is explicitly stated.
- The field tables state structural bounds; cross-field constraints and bounded search or output budgets also apply. Unknown keys are rejected where the object contract disallows them. Input errors are distinct from null fields and deliberate invalid controls in a successful output.
Alternative or Complementary methods
For a supplied example, inspect the returned construction or delegated check directly. To evaluate a consumer, also test cases chosen for its own boundaries; a generated finite corpus does not establish exhaustive coverage.
References
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