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Reduce number of function calls for speedup

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Johannes Schönberger
2013-02-28 23:11:59 +01:00
committed by Johannes Schönberger
parent 2c329d68ec
commit c9353ce8f5
1 changed files with 22 additions and 16 deletions
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skimage/measure/fit.py
+22 -16
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@@ -343,22 +343,22 @@ class EllipseModel(BaseModel):
ct = np.cos(t)
st = np.sin(t)
ctheta = np.cos(theta)
stheta = np.sin(theta)
# derivatives for fx, fy in the following order:
# xc, yc, a, b, theta, t_i
# fx
A[2, :N] = - np.cos(theta) * ct
A[3, :N] = np.sin(theta) * st
A[4, :N] = a * np.sin(theta) * ct + b * np.cos(theta) * st
A[5:, :N][diag_idxs] = a * np.cos(theta) * st \
+ b * np.sin(theta) * ct
A[2, :N] = - ctheta * ct
A[3, :N] = stheta * st
A[4, :N] = a * stheta * ct + b * ctheta * st
A[5:, :N][diag_idxs] = a * ctheta * st + b * stheta * ct
# fy
A[2, N:] = - np.sin(theta) * ct
A[3, N:] = - np.cos(theta) * st
A[4, N:] = - a * np.cos(theta) * ct + b * np.sin(theta) * st
A[5:, N:][diag_idxs] = a * np.sin(theta) * st \
- b * np.cos(theta) * ct
A[2, N:] = - stheta * ct
A[3, N:] = - ctheta * st
A[4, N:] = - a * ctheta * ct + b * stheta * st
A[5:, N:][diag_idxs] = a * stheta * st - b * ctheta * ct
return A
@@ -404,10 +404,14 @@ class EllipseModel(BaseModel):
def Dfun(t, xi, yi):
xt, yt = self.predict_xy(t)
dfx_t = - 2 * (xi - xt) * (- a * np.cos(theta) * np.sin(t)
- b * np.sin(theta) * np.cos(t))
dfy_t = - 2 * (yi - yt) * (- a * np.sin(theta) * np.sin(t)
+ b * np.cos(theta) * np.cos(t))
ct = np.cos(t)
st = np.sin(t)
ctheta = np.cos(theta)
stheta = np.sin(theta)
dfx_t = - 2 * (xi - xt) * (- a * ctheta * st
- b * stheta * ct)
dfy_t = - 2 * (yi - yt) * (- a * stheta * st
+ b * ctheta * ct)
return dfx_t + dfy_t
residuals = np.empty((N, ), dtype=np.double)
@@ -465,9 +469,11 @@ class EllipseModel(BaseModel):
ct = np.cos(t)
st = np.sin(t)
ctheta = np.cos(theta)
stheta = np.sin(theta)
x = xc + a * np.cos(theta) * ct - b * np.sin(theta) * st
y = yc + a * np.sin(theta) * ct + b * np.cos(theta) * st
x = xc + a * ctheta * ct - b * stheta * st
y = yc + a * stheta * ct + b * ctheta * st
return x, y