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authorMattias Andrée <maandree@operamail.com>2014-04-06 00:44:00 +0200
committerMattias Andrée <maandree@operamail.com>2014-04-06 00:44:00 +0200
commit2c10dfc7aa259ad0fd5f3eab8879e870e77fd667 (patch)
tree62e844743d811dd3ba987d170cf1cb8fe71c9f88 /test/cubic_interpolation
parentadd cubic interpolation test, did not work out too well (diff)
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m + fix cubic interpolation
Signed-off-by: Mattias Andrée <maandree@operamail.com>
Diffstat (limited to 'test/cubic_interpolation')
-rwxr-xr-xtest/cubic_interpolation15
1 files changed, 10 insertions, 5 deletions
diff --git a/test/cubic_interpolation b/test/cubic_interpolation
index 249aa89..6d2b22c 100755
--- a/test/cubic_interpolation
+++ b/test/cubic_interpolation
@@ -12,13 +12,16 @@ print('Loading matplotlib.pyplot...')
import matplotlib.pyplot as plot
print('Done loading matplotlib.pyplot')
+from math import *
+
def main():
# Create a page with graphs
fig = plot.figure()
# Add graphs
- add_graph(fig, 111, [i / 15 for i in range(16)])
+ add_graph(fig, 211, [i / 15 for i in range(16)])
+ add_graph(fig, 212, [sin(6 * i / 15) for i in range(16)])
# Show graphs
plot.show()
@@ -45,7 +48,7 @@ def add_graph(fig, graph_pos, input_values):
graph.plot([i / (n - 1) for i in range(n)], input_values, 'ro')
-def interpolate(small):
+def interpolate(small, tension = 0):
'''
Interpolate data
@@ -56,8 +59,8 @@ def interpolate(small):
small_, large_ = len(small) - 1, len(large) - 1
# Basis functions
h00 = lambda t : (1 + 2 * t) * (1 - t) ** 2
- h01 = lambda t : t * (1 - t) ** 2
- h10 = lambda t : t ** 2 * (3 - 2 * t)
+ h10 = lambda t : t * (1 - t) ** 2
+ h01 = lambda t : t ** 2 * (3 - 2 * t)
h11 = lambda t : t ** 2 * (t - 1)
def tangent(values, index, last):
'''
@@ -72,6 +75,8 @@ def interpolate(small):
if index == 0: return values[1] - values[0]
if index == last: return values[last] - values[last - 1]
return (values[index + 1] - values[index - 1]) / 2
+ # Tension coefficent
+ c_ = 1 - tension
for i in range(len(large)):
# Scaling
j = i * small_ / large_
@@ -80,7 +85,7 @@ def interpolate(small):
# Points
pj, pk = small[j], small[k]
# Tangents
- mj, mk = tangent(small, j, small_), tangent(small, k, small_)
+ mj, mk = c_ * tangent(small, j, small_), c_ * tangent(small, k, small_)
# Interpolation
large[i] = h00(w) * pj + h10(w) * mj + h01(w) * pk + h11(w) * mk
return large