| # compute arctangent table for CORDIC computations in fttrigon.c
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| import sys, math
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|
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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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| comma = ""
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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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|
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| for n in range(1,32):
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|
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| x = 0.5**n # tangent value
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|
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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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|
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| if angle2 <= 0:
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| break
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| sys.stdout.write( comma + repr( int(angle2) ) )
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| comma = ", "
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|
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| shrink /= math.sqrt( 1 + x*x )
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|
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| print
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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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|