trader-portfolio-cg

name	trader-portfolio-cg
description	Mean-variance portfolio optimization via Conjugate Gradient — 40-60× faster than the legacy Neumann path (ADR-126 Phase 3, ADR-123 Wedge 8)
allowed-tools	Bash Read mcp__ruflo-sublinear__solve mcp__ruflo__memory_store mcp__ruflo__memory_retrieve mcp__ruflo__memory_search mcp__ruflo__agentdb_pattern-search
argument-hint	[--portfolio-id ID] [--tolerance 1e-6]

Solve the mean-variance optimization Σ · x = μ via Conjugate Gradient instead of the legacy Neumann series.

Why CG instead of Neumann (ADR-123 Wedge 8):

• Neumann series: ~50 µs at n=256 (legacy npx neural-trader --portfolio optimize)
• Conjugate Gradient: ~816 ns at n=256 (this skill)
• Measured speedup: 40-60×; parity within 1e-4 on a fixed seed.

The covariance matrix Σ is symmetric positive-definite by construction (it's a Gram matrix on real returns), so CG is provably optimal — it converges in at most n iterations with no preconditioning, and typically far fewer when eigenvalues cluster.

Disable flag: set RUFLO_NEURAL_TRADER_DISABLE_CG=1 to skip the CG path entirely and fall through to step 4's legacy Neumann route. Useful for A/B validation or when an upstream covariance regression breaks SPD.

Steps:

1. Ensure neural-trader is available:

   npm ls neural-trader 2>/dev/null || npm install --ignore-scripts neural-trader
   

2. Read the current covariance matrix Σ and expected-return vector μ from neural-trader's portfolio API:

   # Primary path (preferred — clean JSON):
   npx neural-trader --portfolio current --json
   # Fallback paths if the --json flag is unavailable on the installed version:
   npx neural-trader --portfolio current  # parse the text output
   # OR pull from AgentDB if a prior run stored the matrix there:
   

   mcp__ruflo__memory_search({ query: "covariance matrix current", namespace: "trading-risk", limit: 1 })
   

   The skill expects the response to include covariance: number[][] (n × n) and expectedReturns: number[] (length n).

3. Solve Σ · x = μ via CG (preferred path) when RUFLO_NEURAL_TRADER_DISABLE_CG is unset and the MCP tool is available:

   mcp__ruflo-sublinear__solve({
     matrix: COVARIANCE,
     rhs: EXPECTED_RETURNS,
     algorithm: "cg",
     tolerance: 1e-6,
     maxIterations: 200
   })
   

   The tool's expected output shape:

   { solution: number[], iterations: number, residual: number }
   

   The skill's adapter (plugins/ruflo-neural-trader/src/sublinear-adapter.ts) detects MCP availability and falls back transparently to the embedded CG kernel (~50 LOC) when mcp__ruflo-sublinear__solve is not registered in the running runtime. Either way the math is identical — CG, dense form, n × n SPD covariance.

4. Fallback (legacy Neumann) — if step 3 reports degraded: true (non-SPD input, non-square matrix, MCP error) OR if RUFLO_NEURAL_TRADER_DISABLE_CG=1:

   npx neural-trader --portfolio optimize
   

   Capture the weights output and tag the artifact metadata with method: 'neumann-fallback' and a reason field.

5. Store the optimal weights to trading-risk namespace with full provenance metadata:

   mcp__ruflo__memory_store({
     key: "portfolio-weights-PORTFOLIO_ID-TIMESTAMP",
     namespace: "trading-risk",
     value: JSON.stringify({
       weights: SOLUTION,                  // number[] from step 3 or 4
       method: 'cg-sublinear' | 'cg-local' | 'neumann-fallback',
       solver: 'ruflo-sublinear@0.1.0',    // or 'neural-trader-cli' on fallback
       iterations: ITERATIONS,
       residual: RESIDUAL,
       latencyMs: LATENCY_MS,
       capturedAt: NEW_DATE_ISO,
       reason: FALLBACK_REASON || null
     })
   })
   

   The trading-risk namespace is canonical (ADR-126 Phase 1; the five-namespace alignment). Long-lived — no TTL — because portfolio weights are the audit trail Phase 4 will Ed25519-sign.

6. Cross-check against historical patterns (optional but recommended):

   mcp__ruflo__agentdb_pattern-search({
     query: "portfolio weights Sharpe regime:CURRENT_REGIME",
     namespace: "trading-risk"
   })
   

   If the new weights differ by more than 30% in any single asset from the historical median, flag for human review before applying. This is a guard-rail, not a hard block.

Acceptance criteria (ADR-126 Phase 3):

• Latency < 1 ms on n = 256 covariance.
• Parity with legacy Neumann within ||cg − neumann||_∞ < 1e-4 on a fixed seed.
• Fallback path engages cleanly when MCP unavailable / covariance non-SPD.
• Artifact metadata distinguishes cg-sublinear, cg-local, and neumann-fallback.

Refs:

• ADR-126 Phase 3 (this skill's authoring ADR)
• ADR-123 §162 Row 8 (Wedge 8 speedup claim)
• ADR-123 §262-289 (the SublinearAdapter contract)
• plugins/ruflo-neural-trader/src/sublinear-adapter.ts (the adapter)
• plugins/ruflo-neural-trader/benchmarks/portfolio-cg.bench.ts (the measured numbers)