(exp 3.2) demonstrate shear inference with all params free but narrow flux/hlr priors

README.md

@@ -23,4 +23,7 @@ git clone [email protected]:LSSTDESC/BPD.git
 cd BPD
 pip install -e .
 pip install -e ".[dev]"
+
+# Might be necessary
+conda install -c nvidia cuda-nvcc
 ```

bpd/draw.py

@@ -3,27 +3,24 @@
 from jax_galsim import GSParams
 
 
+# forward model
 def draw_gaussian(
+    *,
     f: float,
     hlr: float,
     e1: float,
     e2: float,
-    g1: float,
-    g2: float,
-    x: float,
+    x: float,  # pixels
     y: float,
-    *,
     slen: int,
     fft_size: int,  # rule of thumb: at least 4 times `slen`
     psf_hlr: float = 0.7,
     pixel_scale: float = 0.2,
 ):
     gsparams = GSParams(minimum_fft_size=fft_size, maximum_fft_size=fft_size)
 
-    # x, y arguments in pixels
     gal = xgalsim.Gaussian(flux=f, half_light_radius=hlr)
     gal = gal.shear(g1=e1, g2=e2)
-    gal = gal.shear(g1=g1, g2=g2)
 
     psf = xgalsim.Gaussian(flux=1.0, half_light_radius=psf_hlr)
     gal_conv = xgalsim.Convolve([gal, psf]).withGSParams(gsparams)
@@ -32,6 +29,7 @@ def draw_gaussian(
 
 
 def draw_gaussian_galsim(
+    *,
     f: float,
     hlr: float,
     e1: float,
@@ -40,14 +38,17 @@ def draw_gaussian_galsim(
     g2: float,
     x: float,  # pixels
     y: float,
-    *,
     slen: int,
     psf_hlr: float = 0.7,
     pixel_scale: float = 0.2,
 ):
     gal = galsim.Gaussian(flux=f, half_light_radius=hlr)
-    gal = gal.shear(g1=e1, g2=e2)
-    gal = gal.shear(g1=g1, g2=g2)
+    gal = gal.shear(g1=e1, g2=e2)  # intrinsic ellipticity
+
+    # the correct weak lensing effect includes magnification even if kappa=0!
+    # see: https://galsim-developers.github.io/GalSim/_build/html/shear.html
+    mu = (1 - g1**2 - g2**2) ** -1  # convergence kappa = 0
+    gal = gal.lens(g1=g1, g2=g2, mu=mu)
 
     psf = galsim.Gaussian(flux=1.0, half_light_radius=psf_hlr)
     gal_conv = galsim.Convolve([gal, psf])

bpd/likelihood.py

@@ -40,11 +40,7 @@ def shear_loglikelihood(
     interim_logprior: Callable,  # fixed
 ) -> ArrayLike:
     """Shear Likelihood implementation of Schneider et al. 2014."""
-    e_post = post_params["e1e2"]
-    _, _, _ = e_post.shape  # (N, K, 2)
-
     denom = interim_logprior(post_params)
     num = logprior(post_params, g)
-
     ratio = jsp.special.logsumexp(num - denom, axis=-1)
     return ratio.sum()

bpd/pipelines/image_samples.py

@@ -43,29 +43,43 @@ def sample_target_galaxy_params_simple(
     }
 
 
+def get_true_params_from_galaxy_params(galaxy_params: dict[str, Array]):
+    true_params = {**galaxy_params}
+    e1, e2 = true_params.pop("e1"), true_params.pop("e2")
+    g1, g2 = true_params.pop("g1"), true_params.pop("g2")
+
+    e1_prime, e2_prime = scalar_shear_transformation(
+        jnp.array([e1, e2]), jnp.array([g1, g2])
+    )
+    true_params["e1"] = e1_prime
+    true_params["e2"] = e2_prime
+
+    return true_params  # don't add back g1,g2 as we are not inferring those in interim posterior
+
+
 # interim prior
 def logprior(
     params: dict[str, Array],
     *,
     sigma_e: float,
     sigma_x: float = 0.5,  # pixels
     flux_bds: tuple = (-1.0, 9.0),
-    hlr_bds: tuple = (0.01, 5.0),
-    all_free: bool = True,
+    hlr_bds: tuple = (-2.0, 1.0),
+    free_flux_hlr: bool = True,
+    free_dxdy: bool = True,
 ) -> Array:
     prior = jnp.array(0.0)
 
-    if all_free:
+    if free_flux_hlr:
         f1, f2 = flux_bds
         prior += stats.uniform.logpdf(params["lf"], f1, f2 - f1)
 
         h1, h2 = hlr_bds
-        prior += stats.uniform.logpdf(params["hlr"], h1, h2 - h1)
+        prior += stats.uniform.logpdf(params["lhlr"], h1, h2 - h1)
 
-        # NOTE: hard-coded assumption that galaxy is in center-pixel within odd-size image.
-        # sigma_x in units of pixels.
-        prior += stats.norm.logpdf(params["x"], loc=0.0, scale=sigma_x)
-        prior += stats.norm.logpdf(params["y"], loc=0.0, scale=sigma_x)
+    if free_dxdy:
+        prior += stats.norm.logpdf(params["dx"], loc=0.0, scale=sigma_x)
+        prior += stats.norm.logpdf(params["dy"], loc=0.0, scale=sigma_x)
 
     e1e2 = jnp.stack((params["e1"], params["e2"]), axis=-1)
     prior += jnp.log(ellip_prior_e1e2(e1e2, sigma=sigma_e))
@@ -76,17 +90,33 @@ def logprior(
 def loglikelihood(
     params: dict[str, Array],
     data: Array,
+    fixed_params: dict[str, Array],
     *,
     draw_fnc: Callable,
     background: float,
-    free_flux: bool = True,
+    free_flux_hlr: bool = True,
+    free_dxdy: bool = True,
 ):
-    # NOTE: draw_fnc should already contain `f` and `hlr` as constant arguments if fixed
-    _draw_params = {**{"g1": 0.0, "g2": 0.0}, **params}
+    _draw_params = {}
+
+    if free_dxdy:
+        _draw_params["x"] = params["dx"] + fixed_params["x"]
+        _draw_params["y"] = params["dy"] + fixed_params["y"]
+
+    else:
+        _draw_params["x"] = fixed_params["x"]
+        _draw_params["y"] = fixed_params["y"]
+
+    if free_flux_hlr:
+        _draw_params["f"] = 10 ** params["lf"]
+        _draw_params["hlr"] = 10 ** params["lhlr"]
 
-    # Convert log-flux to flux if provided
-    if free_flux:
-        _draw_params["f"] = 10 ** _draw_params.pop("lf")
+    else:
+        _draw_params["f"] = fixed_params["f"]
+        _draw_params["hlr"] = fixed_params["hlr"]
+
+    _draw_params["e1"] = params["e1"]
+    _draw_params["e2"] = params["e2"]
 
     model = draw_fnc(**_draw_params)
     likelihood_pp = stats.norm.logpdf(data, loc=model, scale=jnp.sqrt(background))
@@ -97,24 +127,11 @@ def logtarget(
     params: dict[str, Array],
     data: Array,
     *,
+    fixed_params: dict[str, Array],
     logprior_fnc: Callable,
     loglikelihood_fnc: Callable,
 ):
-    return logprior_fnc(params) + loglikelihood_fnc(params, data)
-
-
-def get_true_params_from_galaxy_params(galaxy_params: dict[str, Array]):
-    true_params = {**galaxy_params}
-    e1, e2 = true_params.pop("e1"), true_params.pop("e2")
-    g1, g2 = true_params.pop("g1"), true_params.pop("g2")
-
-    e1_prime, e2_prime = scalar_shear_transformation(
-        jnp.array([e1, e2]), jnp.array([g1, g2])
-    )
-    true_params["e1"] = e1_prime
-    true_params["e2"] = e2_prime
-
-    return true_params  # don't add g1,g2 back as we are not inferring those in interim posterior
+    return logprior_fnc(params) + loglikelihood_fnc(params, data, fixed_params)
 
 
 def get_target_images_single(
@@ -156,30 +173,27 @@ def pipeline_interim_samples_one_galaxy(
     rng_key: PRNGKeyArray,
     true_params: dict[str, float],
     target_image: Array,
-    fixed_draw_kwargs: dict,
+    fixed_params: dict[str, float],
     *,
     initialization_fnc: Callable,
-    draw_fnc: Callable,
     logprior: Callable,
+    loglikelihood: Callable,
     n_samples: int = 100,
     max_num_doublings: int = 5,
     initial_step_size: float = 1e-3,
     n_warmup_steps: int = 500,
     is_mass_matrix_diagonal: bool = True,
-    background: float = 1.0,
-    free_flux: bool = True,
 ):
     # Flux and HLR are fixed to truth and not inferred in this function.
     k1, k2 = random.split(rng_key)
 
     init_position = initialization_fnc(k1, true_params=true_params, data=target_image)
-    _draw_fnc = partial(draw_fnc, **fixed_draw_kwargs)
-    _loglikelihood = partial(
-        loglikelihood, draw_fnc=_draw_fnc, background=background, free_flux=free_flux
-    )
 
     _logtarget = partial(
-        logtarget, logprior_fnc=logprior, loglikelihood_fnc=_loglikelihood
+        logtarget,
+        logprior_fnc=logprior,
+        loglikelihood_fnc=loglikelihood,
+        fixed_params=fixed_params,
     )
 
     _inference_fnc = partial(

experiments/exp2/run_inference_galaxy_images.py

@@ -3,11 +3,13 @@
 
 import time
 from functools import partial
+from typing import Callable
 
 import jax.numpy as jnp
 import typer
-from jax import jit, random, vmap
+from jax import Array, jit, random, vmap
 from jax._src.prng import PRNGKeyArray
+from jax.scipy import stats
 
 from bpd import DATA_DIR
 from bpd.chains import run_sampling_nuts, run_warmup_nuts
@@ -16,11 +18,58 @@
 from bpd.pipelines.image_samples import (
     get_target_images,
     get_true_params_from_galaxy_params,
-    loglikelihood,
-    logprior,
-    logtarget,
     sample_target_galaxy_params_simple,
 )
+from bpd.prior import ellip_prior_e1e2
+
+
+def logprior(
+    params: dict[str, Array],
+    *,
+    sigma_e: float,
+    sigma_x: float = 0.5,  # pixels
+    flux_bds: tuple = (-1.0, 9.0),
+    hlr_bds: tuple = (0.01, 5.0),
+) -> Array:
+    prior = jnp.array(0.0)
+
+    f1, f2 = flux_bds
+    prior += stats.uniform.logpdf(params["lf"], f1, f2 - f1)
+
+    h1, h2 = hlr_bds
+    prior += stats.uniform.logpdf(params["hlr"], h1, h2 - h1)
+
+    prior += stats.norm.logpdf(params["x"], loc=0.0, scale=sigma_x)
+    prior += stats.norm.logpdf(params["y"], loc=0.0, scale=sigma_x)
+
+    e1e2 = jnp.stack((params["e1"], params["e2"]), axis=-1)
+    prior += jnp.log(ellip_prior_e1e2(e1e2, sigma=sigma_e))
+
+    return prior
+
+
+def loglikelihood(
+    params: dict[str, Array],
+    data: Array,
+    *,
+    draw_fnc: Callable,
+    background: float,
+):
+    _draw_params = {**params}
+    _draw_params["f"] = 10 ** _draw_params.pop("lf")
+    model = draw_fnc(**_draw_params)
+    likelihood_pp = stats.norm.logpdf(data, loc=model, scale=jnp.sqrt(background))
+    return jnp.sum(likelihood_pp)
+
+
+def logtarget(
+    params: dict[str, Array],
+    data: Array,
+    *,
+    logprior_fnc: Callable,
+    loglikelihood_fnc: Callable,
+):
+    return logprior_fnc(params) + loglikelihood_fnc(params, data)
 
 
 def sample_prior(
@@ -67,7 +116,7 @@ def main(
     pkey, nkey, ikey, rkey = random.split(rng_key, 4)
 
     # directory structure
-    dirpath = DATA_DIR / "cache_chains" / f"test_image_sampling_{seed}"
+    dirpath = DATA_DIR / "cache_chains" / f"exp2_{seed}"
     if not dirpath.exists():
         dirpath.mkdir(exist_ok=True)
     fpath = dirpath / f"chain_results_{seed}.npy"

experiments/exp3/README.md → experiments/exp30/README.md

@@ -1,4 +1,4 @@
-# Experiment 3
+# Experiment 3.0
 
 This folder contains scripts to reproduce results on fitting galaxy images in the low noise setting
 and inferring shear from them. Details: