33 lines
770 B
Python
33 lines
770 B
Python
#!/usr/bin/env python3
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# compute arctangent table for CORDIC computations in fttrigon.c
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import math
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# units = 64*65536.0 # don't change !!
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units = 180 * 2 ** 16
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scale = units / math.pi
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shrink = 1.0
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angles2 = []
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print("")
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print("table of arctan( 1/2^n ) for PI = " + repr(units / 65536.0) + " units")
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for n in range(1, 32):
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x = 0.5 ** n # tangent value
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angle = math.atan(x) # arctangent
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angle2 = round(angle * scale) # arctangent in FT_Angle units
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if angle2 <= 0:
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break
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angles2.append(repr(int(angle2)))
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shrink /= math.sqrt(1 + x * x)
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print(", ".join(angles2))
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print("shrink factor = " + repr(shrink))
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print("shrink factor 2 = " + repr(int(shrink * (2 ** 32))))
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print("expansion factor = " + repr(1 / shrink))
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print("")
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