Initial commit of the evolving_fisher component. Why do we see the Fisher we do?

Author: aribenjamin

evolving_fisher/__init__.py

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+from .fisher_calculators import *

evolving_fisher/deep-linear-simulation.ipynb

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+
+import numpy as np
+
+import matplotlib.pyplot as plt
+
+import torch
+import torch.nn as nn
+from torchvision import models, transforms
+
+import argparse
+import pickle
+
+
+############################ Generators from Linqi's code ##########################################
+
+def gen_sinusoid(sz, A, omega, rho):
+    radius = int(sz / 2.0)
+    [x, y] = torch.meshgrid([torch.tensor(range(-radius, radius)),
+                             torch.tensor(range(-radius, radius))])
+    x = x.float()
+    y = y.float()
+    stimuli = A * torch.cos(0.35 * omega[0] * x + 0.35 * omega[1] * y + rho)
+    return stimuli
+
+
+def gen_sinusoid_aperture(ratio, sz, A, omega, rho, polarity):
+    sin_stimuli = gen_sinusoid(sz, A, omega, rho)
+    radius = int(sz / 2.0)
+    [x, y] = torch.meshgrid([torch.tensor(range(-radius, radius)),
+                             torch.tensor(range(-radius, radius))])
+    aperture = torch.empty(sin_stimuli.size(), dtype=torch.float)
+
+    aperture_radius = float(radius) * ratio
+    aperture[x ** 2 + y ** 2 >= aperture_radius ** 2] = 1 - polarity
+    aperture[x ** 2 + y ** 2 < aperture_radius ** 2] = polarity
+
+    return sin_stimuli * aperture
+
+
+def center_surround(ratio, sz, theta_center, theta_surround, A, rho):
+    center = gen_sinusoid_aperture(ratio, sz, A, [torch.cos(theta_center), torch.sin(theta_center)], rho, 1)
+    surround = gen_sinusoid_aperture(ratio, sz, A, [torch.cos(theta_surround), torch.sin(theta_surround)], rho, 0)
+    return center + surround
+
+
+def sinsoid_noise(ratio, sz, A, omega, rho):
+    radius = int(sz / 2.0)
+    sin_aperture = gen_sinusoid_aperture(ratio, sz, A, omega, rho, 1)
+
+    nrm_dist = normal.Normal(0.0, 0.12)
+    noise_patch = nrm_dist.sample(sin_aperture.size())
+
+    [x, y] = torch.meshgrid([torch.tensor(range(-radius, radius)),
+                             torch.tensor(range(-radius, radius))])
+    aperture = torch.empty(sin_aperture.size(), dtype=torch.float)
+
+    aperture_radius = float(radius) * ratio
+    aperture[x ** 2 + y ** 2 >= aperture_radius ** 2] = 1
+    aperture[x ** 2 + y ** 2 < aperture_radius ** 2] = 0
+
+    return noise_patch * aperture + sin_aperture
+
+
+def rgb_sinusoid(theta):
+    output = torch.zeros(1, 3, 224, 224)
+    sin_stim = gen_sinusoid(224, A=1, omega=[torch.cos(theta), torch.sin(theta)], rho=0)
+    for idx in range(3):
+        output[0, idx, :, :] = sin_stim
+
+    return output
+
+
+def rgb_sine_aperture(theta):
+    output = torch.zeros(1, 3, 224, 224)
+    sin_stim = gen_sinusoid_aperture(0.85, 224, A=1, omega=[torch.cos(theta), torch.sin(theta)], rho=0, polarity=1)
+#     show_stimulus(sin_stim)
+    for idx in range(3):
+        output[0, idx, :, :] = sin_stim
+
+    return output
+
+
+def rgb_sine_noise(theta):
+    output = torch.zeros(1, 3, 224, 224)
+    sin_stim = sinsoid_noise(0.75, 224, A=1, omega=[torch.cos(theta), torch.sin(theta)], rho=0)
+    for idx in range(3):
+        output[0, idx, :, :] = sin_stim
+
+    return output
+
+
+def rgb_center_surround(theta_center, theta_surround):
+    output = torch.zeros(1, 3, 224, 224)
+    stimulus = center_surround(0.75, 224, theta_center, theta_surround, A=1, rho=0)
+    for idx in range(3):
+        output[0, idx, :, :] = stimulus
+    return output
+
+
+def show_stimulus(I):
+    plt.figure()
+    plt.axis('off')
+    plt.imshow(I.detach().numpy(), cmap=plt.gray())
+    plt.show()
+
+##################################################################################################
+
+
+def get_fisher_orientations(model, layer, n_angles=120, n_phases=1, delta = 1e-2):
+    """ Takes a full model (unchopped) along with a layer specification, and returns the fisher information
+    with respect to orientation of that layer (averaged over phase of sine grating).
+
+    Also allows choosing the finite-difference delta
+
+    :param n_images: number of phases to average over. Sampled randomly"""
+
+
+    phases = np.linspace(0, np.pi, n_phases)
+    angles = np.linspace(0, np.pi, n_angles)
+
+
+    # create negative mask. This is a circle centered in the middle of radius 100 pixels
+    unit_circle = np.zeros((224, 224)).astype(np.bool)
+    for i in range(224):
+        for j in range(224):
+            if (i - 112) ** 2 + (j - 112) ** 2 >= 50 ** 2:
+                unit_circle[i, j] = True
+
+
+    fishers_at_angle = []
+    for angle in angles:
+        #         print("\n angle",angle)
+        """I'll put all phases in one giant tensor for faster torching"""
+        all_phases_plus = torch.zeros(n_phases ,3 ,224 ,224).cuda()
+        all_phases_minus = torch.zeros(n_phases ,3 ,224 ,224).cuda()
+
+        for i ,phase in enumerate(phases):
+
+
+            all_phases_plus[i] = rgb_sine_aperture(torch.tensor( angle +delta))
+            all_phases_minus[i] = rgb_sine_aperture(torch.tensor( angle -delta))
+
+        # get the response
+        plus_resp = get_response(all_phases_plus, model, layer)
+
+        size = plus_resp.size()
+
+        minus_resp = get_response(all_phases_minus, model, layer)
+
+        # get the derivative. Now working in pytorch
+        df_dtheta = get_derivative(delta, plus_resp, minus_resp)
+        # reshape to be in terms of examples
+        df_dtheta = df_dtheta.view(n_phases ,-1)
+
+        # average down
+        fisher = get_fisher(df_dtheta)
+        fishers_at_angle.append(fisher)
+    # print("fisher",fisher)
+    print("response size", size)
+    return fishers_at_angle
+
+def get_derivative(delta, plus_resp, minus_resp):
+    """
+    Calculates the finite-difference derivative of the network activation w/r/t the relative angle between two lines
+    :param delta: The perturbation
+    :param minus_resp: The activations at the negative perturbation
+    :param plus_resp: The activations at the positive perturbation
+
+    :return: The derivative of the activations of the network at specified layer. FLATTENED
+
+    >>> f = lambda x: x**2
+    >>> d = get_derivative(1e-3, f(2+1e-3), f(2-1e-3))
+    >>> assert np.isclose(d,4)
+    >>> d = get_derivative(1e-3, f(5+1e-3), f(5-1e-3))
+    >>> assert np.isclose(d,10)
+    """
+
+    deriv = (plus_resp - minus_resp )/ (2 * delta)
+    return deriv
+
+
+def get_fisher(df_dtheta):
+    """
+    Compute fisher information under Gaussian noise assumption. 
+
+    Averages over the 0th dimension. (Assumes they're specific examples)
+
+    :param df_dtheta: Derivative of a function f w/r/t some parameter theta
+    :return: The Fisher information (1-dimensional)
+    """
+
+    fishers = 0
+    for d in df_dtheta:
+        fishers += torch.dot(d ,d)
+    fisher = fishers/ len(df_dtheta)
+
+    return fisher
+
+
+def numpy_to_torch(rgb_image, cuda=True):
+    """
+    Prepares an image for passing through a pytorch network.
+    :param rgb_image: Numpy tensor, shape (x,y,3)
+    :return: Pytorch tensor, shape (3,x,y), with channels switched to BGR.
+
+    >>> numpy_to_torch(np.ones((224,224,3))).size()
+    torch.Size([3, 224, 224])
+    """
+
+    # rgb to bgr
+    tens = torch.from_numpy(rgb_image[:, :, [2, 1, 0]])
+    if cuda:
+        r = tens.permute(2, 0, 1).float().cuda()
+    else:
+        r = tens.permute(2, 0, 1).float()
+    return r
+
+
+def get_response(torch_image, model, layer):
+    """
+    Gets the response of the network of the VGG at a certain layer to a single image
+    NOTE: we only return the activations corresponding to the center of the image.
+
+    Assumes the network is on the GPU already.
+
+
+
+    :param image: An torch image
+    :param layer: which layer? 4,9,16,23,30
+    :param hooked_model: A model with a 
+    :return: Pytorch tensor of the activations
+    """
+
+    # preprocess image
+    mean = torch.Tensor([[[0.485]], [[0.456]], [[0.406]]]).cuda()
+    std = torch.Tensor([[[0.229]], [[0.224]], [[0.225]]]).cuda()
+
+    torch_image = (torch_image - mean) / std
+
+    # indexing by None adds a new axis in the beginning
+    if len(torch_image.size()) == 3:
+        torch_image = torch_image[None]
+
+        # register the hook
+    outputs_at_layer = []
+
+    def hook(module, input, output):
+        outputs_at_layer.append(output.detach())
+
+    # vgg/alexnet or resnet?
+    if len(list(model.children())) > 4:
+        handle = list(model.children())[layer].register_forward_hook(hook)
+    else:
+        handle = list(model.children())[0][layer].register_forward_hook(hook)
+
+    _ = model(torch_image)
+
+    # clean up
+    handle.remove()
+    r = outputs_at_layer[0]
+    del outputs_at_layer
+    return r