f43322e5ce
All checks were successful
ci/woodpecker/push/woodpecker Pipeline was successful
The user noticed the "Annual spending" field was a no-op for Trinity,
GK, VPW, VPW+floor — the strategies internally hardcoded the year-0
withdrawal as `initial_portfolio × initial_rate` (4% / 5.5%) and
ignored what the user typed. Two fixes:
(1) Trinity + GK now use state.initial_withdrawal (= the user's
spending_target) as the year-0 draw. GK's guardrail anchor
becomes the implied initial rate (initial_withdrawal /
initial_portfolio), so the rule shape adapts to the user's
chosen rate. Both strategies still fall back to their preset
rate × initial_portfolio when initial_withdrawal isn't set
(test paths). VPW and VPW+floor stay algorithmic — they're
"withdraw-what's-sustainable" by design and don't take a
spending input.
(2) New "custom" preset (SpendingPlanStrategy) exposing all the
knobs:
- initial_spend = "Annual spending" input
- annual_real_adjust_pct = scale last year's withdrawal by N%
each year (0 = constant real £, +0.02 = 2%/yr healthcare
creep, -0.005 = -0.5%/yr slow-down with age)
- guardrail_threshold_pct = if portfolio falls below X% of
starting NW, trigger a cut (None = disabled)
- guardrail_cut_pct = cut last year's withdrawal by Y% each
triggered year
Adjust applies first, then guardrail cut — so a triggered year in
+2% adjust mode goes 40k → 40.8k → 36.7k.
UI: "custom" added to the strategy dropdown; when selected, three
extra fields appear (annual real adjustment %, guardrail trigger
threshold, guardrail cut size) with hints. The existing inputs
(spending, NW seed) drive year 0 across all strategies that use
them. About-the-model panel updated.
10 new tests on SpendingPlanStrategy + adjusted GK tests for the
new spending_target-aware behaviour. 209 backend tests + 7
frontend tests. mypy + ruff + tsc all pass.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
62 lines
2.5 KiB
Python
62 lines
2.5 KiB
Python
"""Custom user-defined spending plan.
|
|
|
|
A flexible strategy where the user chooses every knob:
|
|
|
|
- `initial_spend` — year 0 withdrawal in real GBP (taken from
|
|
`state.initial_withdrawal` if not overridden).
|
|
- `annual_real_adjust_pct` — fraction by which last year's withdrawal
|
|
scales each subsequent year, on top of inflation. 0.0 = constant
|
|
real GBP (Trinity-shape). +0.02 = 2%/yr above-inflation creep
|
|
(e.g. healthcare). -0.005 = -0.5%/yr decreasing spend (slowing
|
|
down with age).
|
|
- `guardrail_threshold_pct` — if portfolio drops below this fraction
|
|
of the starting NW, apply a cut. None = no guardrail.
|
|
- `guardrail_cut_pct` — fraction by which to cut last year's
|
|
withdrawal when triggered. Applied multiplicatively each triggered
|
|
year — not "snap to threshold-implied rate", just a soft cut.
|
|
|
|
The cut is checked AFTER the annual adjustment, so a cut + an
|
|
increase don't double-apply: cut wins.
|
|
|
|
Compared to Guyton-Klinger this is simpler — one threshold, one
|
|
cut size, no prosperity rule. If the user wants the prosperity rule
|
|
behaviour they can pick the GK preset.
|
|
"""
|
|
from __future__ import annotations
|
|
|
|
from fire_planner.strategies.base import StrategyState, WithdrawalStrategy
|
|
|
|
|
|
class SpendingPlanStrategy(WithdrawalStrategy):
|
|
name = "custom"
|
|
|
|
def __init__(
|
|
self,
|
|
initial_spend: float | None = None,
|
|
annual_real_adjust_pct: float = 0.0,
|
|
guardrail_threshold_pct: float | None = None,
|
|
guardrail_cut_pct: float = 0.10,
|
|
) -> None:
|
|
self.initial_spend = initial_spend
|
|
self.annual_real_adjust_pct = annual_real_adjust_pct
|
|
self.guardrail_threshold_pct = guardrail_threshold_pct
|
|
self.guardrail_cut_pct = guardrail_cut_pct
|
|
|
|
def propose_withdrawal(self, state: StrategyState) -> float:
|
|
if state.year_idx == 0:
|
|
# Explicit override wins; otherwise take the user's target.
|
|
return (self.initial_spend
|
|
if self.initial_spend is not None and self.initial_spend > 0 else
|
|
state.initial_withdrawal)
|
|
if state.portfolio <= 0:
|
|
return 0.0
|
|
|
|
proposed = state.last_withdrawal * (1.0 + self.annual_real_adjust_pct)
|
|
|
|
if (self.guardrail_threshold_pct is not None
|
|
and state.initial_portfolio > 0):
|
|
trigger_at = state.initial_portfolio * self.guardrail_threshold_pct
|
|
if state.portfolio < trigger_at:
|
|
proposed = proposed * (1.0 - self.guardrail_cut_pct)
|
|
|
|
return max(0.0, proposed)
|