Bump to 0.9.0

.github/copilot-instructions.md

@@ -45,25 +45,3 @@ applyTo: '/**'
 
 * Strategy runtime markdown descriptions (read by `load_description()` at runtime) live inside the package at `quantflow/options/strategies/docs/` — they must be inside the package to be accessible when the library is installed
 * mkdocs documentation pages live in `docs/api/options/` — do not mix these two locations
-
-## Releasing
-
-The release procedure is fully driven by `make release` and the `release.yml` workflow:
-
-1. Bump `version` in `pyproject.toml` to the new release version.
-2. Add a `## vX.Y.Z` section to `docs/release-notes.md` with the notes for the release. The header text is matched verbatim by the workflow's `awk` extractor, so it must be `## vX.Y.Z` exactly (no trailing dash, no title after the version).
-3. Commit and merge to `main`.
-4. From `main`, run `make release` — it reads the version from `pyproject.toml`, prompts for confirmation, then creates an annotated `vX.Y.Z` tag and pushes it.
-5. The tag push triggers `.github/workflows/release.yml`, which runs lint and tests, publishes the package to PyPI (`make publish`), and posts the extracted `## vX.Y.Z` section as the GitHub Release body.
-
-Do not publish to PyPI manually or via the old `head_commit.message == 'release'` flow — the tag-triggered workflow is the only supported path.
-
-### Release-notes conventions
-
-The `## vX.Y.Z` section in `docs/release-notes.md` must follow these conventions, since the same content is rendered both on the docs site and as the GitHub Release body:
-
-* Open with a one-paragraph summary describing the theme of the release. If the release contains breaking changes, point readers to the **Breaking changes** section in that paragraph.
-* Group entries under H3 subsections in this order: `### Breaking changes`, `### New features`, `### Improvements and fixes`, `### Documentation and assets`. Omit any subsection that has no entries.
-* Every PR reference must be a markdown link of the form `[#NN](https://github.com/quantmind/quantflow/pull/NN)`. Never write a bare `(#NN)` — both readers (docs and GitHub) benefit from the explicit URL, and GitHub's auto-linking only works in some contexts. When a single entry references multiple PRs, list them comma-separated inside one set of parentheses, each as its own markdown link.
-* Build the PR list by running `git log vPREV..HEAD --oneline` against the previous release tag and following each squashed-merge commit back to its PR. Cross-check with `gh pr list --state merged --base main` for any PRs merged since the previous tag.
-* End the section with a `[Full changelog](https://github.com/quantmind/quantflow/compare/vPREV...vX.Y.Z)` link comparing the new tag against the previous one.

.github/instructions/release.instructions.md

@@ -0,0 +1,48 @@
+# Release Instructions
+
+Releases are driven by `v*` git tags. Pushing a tag triggers
+`.github/workflows/release.yml`, which runs lint and the test suite, publishes
+the package to PyPI (`make publish`), then extracts the matching `## vX.Y.Z`
+section from `docs/release-notes.md` and publishes it as the GitHub Release
+body.
+
+## Cutting a release
+
+1. Bump `version` in `pyproject.toml` to the new release version.
+2. Add a `## vX.Y.Z` section at the top of `docs/release-notes.md` with the
+   notes for the release. The header text is matched verbatim by the
+   workflow's `awk` extractor, so it must be `## vX.Y.Z` exactly (no trailing
+   dash, no title after the version). The release workflow fails if this
+   section is missing.
+3. Commit and merge to `main`; let the `build` workflow pass.
+4. From `main`, run `make release` — it reads the version from
+   `pyproject.toml`, asks for confirmation, then creates an annotated `vX.Y.Z`
+   tag and pushes it. The `release` workflow takes it from there.
+
+Do not publish to PyPI manually, and do not revive the old
+`head_commit.message == 'release'` flow — the tag-triggered workflow is the
+only supported path.
+
+## Release-notes conventions
+
+The `## vX.Y.Z` section in `docs/release-notes.md` is rendered both on the
+docs site and as the GitHub Release body, so it must follow these conventions:
+
+- Open with a one-paragraph summary describing the theme of the release. If
+  the release contains breaking changes, point readers to the **Breaking
+  changes** section in that paragraph.
+- Group entries under H3 subsections in this order: `### Breaking changes`,
+  `### New features`, `### Improvements and fixes`,
+  `### Documentation and assets`. Omit any subsection that has no entries.
+- Every PR reference must be a markdown link of the form
+  `[#NN](https://github.com/quantmind/quantflow/pull/NN)` — never a bare
+  `(#NN)`. GitHub's auto-linking only works in some contexts, and the explicit
+  URL works everywhere. When one entry references multiple PRs, list them
+  comma-separated inside one set of parentheses, each as its own link.
+- Build the PR list by running `git log vPREV..HEAD --oneline` against the
+  previous release tag and following each squashed-merge commit back to its
+  PR. Cross-check with `gh pr list --state merged --base main` for any PRs
+  merged since the previous tag.
+- End the section with a
+  `[Full changelog](https://github.com/quantmind/quantflow/compare/vPREV...vX.Y.Z)`
+  link comparing the new tag against the previous one.

CLAUDE.md

@@ -1,4 +1,5 @@
 @readme.md
 @.github/copilot-instructions.md
 @.github/instructions/makefile.instructions.md
+@.github/instructions/release.instructions.md
 @.github/instructions/tutorial.instructions.md

docs/release-notes.md

@@ -6,6 +6,94 @@ below maps to a tagged release on
 pushed, the matching section is extracted by
 `.github/workflows/release.yml` and published as the GitHub Release body.
 
+## v0.9.0
+
+Pricing-engine and calibration overhaul. `MaturityPricer` now evaluates call
+prices and Greeks lazily at arbitrary log-strikes instead of carrying a
+precomputed grid, Fourier pricers take a moneyness-based truncation parameter,
+and the volatility-surface calibration can fit Black implied vols directly.
+This release contains several API changes: see **Breaking changes** below.
+
+### Breaking changes
+
+**`MaturityPricer` reworked.** ([#59](https://github.com/quantmind/quantflow/pull/59))
+
+- The precomputed `std`, `log_strike` and `call` arrays are gone. A
+  `MaturityPricer` now holds a single `pricing` field (an
+  `OptionPricingResult`) that evaluates call prices and Greeks on demand at
+  any log-strike.
+- `moneyness` is now a method, `moneyness(log_strikes)`, not a cached array
+  property. The `time_value` and `intrinsic_value` array properties and the
+  `interp(...)` helper were removed; use `prices(log_strikes)` to get a
+  DataFrame of prices and implied vols on a chosen log-strike grid.
+
+**Fourier pricing truncation: `max_log_strike` → moneyness parameters.**
+([#59](https://github.com/quantmind/quantflow/pull/59))
+
+- `Marginal1D.call_option`, `call_option_carr_madan` and `call_option_lewis`
+  take `max_moneyness` (a multiple of the marginal standard deviation)
+  instead of `max_log_strike`. The COS path takes
+  `cos_moneyness_std_precision` instead.
+- `OptionPricingResult.call_at(...)` is renamed `call_price(...)`, the
+  `method` field is removed, and a new abstract `call_greeks(log_strike)`
+  returns a `Greeks` namedtuple `(price, delta, gamma)`.
+
+**`OptionPricerBase.call_price` → `call_prices`.**
+([#59](https://github.com/quantmind/quantflow/pull/59)) The method is now
+vectorised: it takes arrays of times-to-maturity and log-strikes and prices
+them in a single maturity-grouped call.
+
+**`DIVFMPricer` no longer builds a fixed moneyness grid.**
+([#59](https://github.com/quantmind/quantflow/pull/59)) The
+`max_moneyness_ttm` and `n` fields are removed; the fitted IV surface is
+evaluated on demand through `OptionPricingResultDIVFM`.
+
+### New features
+
+- **Implied-vol calibration residuals.** New `ResidualKind` enum and a
+  `residual_kind` field on `VolModelCalibration`: set it to `ResidualKind.IV`
+  to fit the model to Black implied vols (recovered by inverting the model
+  price) rather than to forward-space prices. The IV residual is naturally
+  well-scaled across moneyness, so `moneyness_weight` is not applied in that
+  mode. ([#59](https://github.com/quantmind/quantflow/pull/59))
+- **Greeks from the pricing result.** `OptionPricingCosResult.call_greeks`
+  returns closed-form price, delta and gamma from the COS expansion; the
+  transform-based result derives delta and gamma by differentiating the call
+  grid; DIVFM uses finite differences on the fitted surface.
+  ([#59](https://github.com/quantmind/quantflow/pull/59))
+- **COS truncation control on `OptionPricer`.** New
+  `cos_moneyness_std_precision` field (default 12) sets the width of the COS
+  integration interval in standard deviations.
+  ([#59](https://github.com/quantmind/quantflow/pull/59))
+
+### Improvements and fixes
+
+- Calibration residuals are now computed in a single vectorised pricing call.
+  Deep-wing strikes where the model price falls outside the no-arbitrage band
+  (so Newton fails to invert it) are masked out instead of poisoning the fit,
+  and a parameter set that fails to invert on more than half the options is
+  rejected with a large penalty.
+  ([#59](https://github.com/quantmind/quantflow/pull/59))
+- Calibration plots now evaluate the model on a fresh moneyness grid;
+  `plot(max_moneyness=...)` no longer accepts `None`.
+  ([#59](https://github.com/quantmind/quantflow/pull/59))
+- `OptionEntry.mid_price()` no longer caches through a private attribute.
+  ([#59](https://github.com/quantmind/quantflow/pull/59))
+- Stale Jupytext notebook mirrors under `notebooks/` removed.
+  ([#59](https://github.com/quantmind/quantflow/pull/59))
+
+### Documentation and assets
+
+- New GitHub social-preview banner under `docs/assets/logos/png/`.
+  ([#59](https://github.com/quantmind/quantflow/pull/59))
+- `docs/api/options/black.md` and the volatility-surface calibration examples
+  updated for the new pricer API.
+  ([#59](https://github.com/quantmind/quantflow/pull/59))
+- The release procedure moved out of `.github/copilot-instructions.md` into
+  its own `.github/instructions/release.instructions.md`.
+
+[Full changelog](https://github.com/quantmind/quantflow/compare/v0.8.0...v0.9.0)
+
 ## v0.8.0
 
 Volatility-surface calibration overhaul. This release adds a two-factor BNS

pyproject.toml

@@ -1,6 +1,6 @@
 [project]
 name = "quantflow"
-version = "0.8.0"
+version = "0.9.0"
 description = "quantitative analysis"
 authors = [ { name = "Luca Sbardella", email = "luca@quantmind.com" } ]
 license = "BSD-3-Clause"