From 626a1a3c73ee1395712002cf7d90c6d00b1cc3bf Mon Sep 17 00:00:00 2001
From: Aaron LI <aly@aaronly.me>
Date: Fri, 3 Nov 2017 18:33:45 +0800
Subject: Remove python/force_field_transform.py

---
 python/force_field_transform.py | 126 ----------------------------------------
 1 file changed, 126 deletions(-)
 delete mode 100644 python/force_field_transform.py

diff --git a/python/force_field_transform.py b/python/force_field_transform.py
deleted file mode 100644
index 2b185c8..0000000
--- a/python/force_field_transform.py
+++ /dev/null
@@ -1,126 +0,0 @@
-# -*- coding: utf -*-
-#
-# Force field transform (Hurley et al., 2002, 2005)
-#
-
-"""
-Force field transform
-"""
-
-import sys
-import time
-import numpy as np
-
-
-def force(p1, p2):
-    """
-    The force between two points of the image.
-
-    Arguments:
-        p1, p2: (value, x, y)
-
-    Return:
-    #    (force, angle): value and direction of the force.
-    #                    angle: (-pi, pi], with respect to p1.
-        (f_x, f_y): x and y components of the force
-    """
-    v1, x1, y1 = p1
-    v2, x2, y2 = p2
-    #force = v1*v2 / ((x1-x2)**2 + (y1-y2)**2)
-    #angle = np.atan2(y2-y1, x2-x1)
-    #return (force, angle)
-    f_x = v1 * v2 * (x2-x1) / ((x2-x1)**2 + (y2-y1)**2)**1.5
-    f_y = v1 * v2 * (y2-y1) / ((x2-x1)**2 + (y2-y1)**2)**1.5
-    return (f_x, f_y)
-
-
-def force_array(p0, img):
-    """
-    The forces between the input point with respect to the image.
-
-    Arguments:
-        p0: (x, y), note (x, y) start with zero.
-        img: input image, a numpy array
-
-    Return:
-        (f_x, f_y): x and y components of the forces of the same size
-                    of the input image
-    """
-    x0, y0 = p0
-    v0 = img[y0, x0]
-    img[y0, x0] = 0.0
-    x, y = np.meshgrid(range(img.shape[1]), range(img.shape[0]))
-    x[y0, x0] = -1
-    y[y0, x0] = -1
-    f_x = v0 * img * (x-x0) / ((x-x0)**2 + (y-y0)**2)**1.5
-    f_y = v0 * img * (y-y0) / ((x-x0)**2 + (y-y0)**2)**1.5
-    return (f_x, f_y)
-
-
-def vector_add(v1, v2):
-    """
-    Add two vectors and return the results.
-
-    Arguments:
-        v1, v2: two input vectors of format (f_x, f_y)
-
-    Return:
-        (F_x, F_y)
-    """
-    f1_x, f1_y = v1
-    f2_x, f2_y = v2
-    return (f1_x+f2_x, f1_y+f2_y)
-
-
-def force_summation(pixel, img):
-    """
-    Calculate the resulting force of the specified pixel with respect to
-    the image.
-
-    Argument:
-        pixel: the position (x, y) of the pixel to be calculated
-        img: the input image
-
-    Return:
-        (F_x, F_y): x and y components of the resulting force.
-    """
-    img = np.array(img)
-    x0, y0 = pixel
-    f_x, f_y = force_array((x0, y0), img)
-    return (f_x.sum(), f_y.sum())
-
-
-def force_field_transform(img):
-    """
-    Perform the "force field transform" on the input image.
-
-    Arguments:
-        img: input 2D image
-
-    Return:
-        (amplitudes, angles)
-        amplitudes: the amplitudes of the resulting forces of each pixel
-        angles: the directions of the resulting forces of each pixel,
-                    in unit radian.
-    """
-    img = np.array(img)
-    amplitudes = np.zeros(img.shape)
-    angles = np.zeros(img.shape)
-    rows, cols = img.shape
-    t0 = time.time()
-    t_p = t0 + 30  # in 30 seconds
-    for y in range(rows):
-        for x in range(cols):
-            t1 = time.time()
-            if t1 >= t_p:
-                percent = 100 * (y*cols + x + 1) / (rows * cols)
-                print("progress: %.3f%%; %.1f min" % (percent, (t1-t0)/60.0),
-                        file=sys.stderr)
-                t_p += 30  # in 30 seconds
-            f_x, f_y = force_array((x, y), img)
-            F_x, F_y = f_x.sum(), f_y.sum()
-            amplitudes[y, x] = np.sqrt(F_x**2 + F_y**2)
-            angles[y, x] = np.math.atan2(F_y, F_x)
-    return (amplitudes, angles)
-
-
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