Calculate closest series R pair (or parallel C pair) to a given value

gistfile1.txt

#!/usr/bin/env python
import math
import numpy as np

#calc two series R or two parallel C that produce the closest result
target = int(float(raw_input("Target value: "))*100)
tolerance = float(raw_input("Tolerance (1 or 5): "))

if tolerance == 5:
    stdvals = [10, 12, 15, 18, 22, 27, 33, 39, 47, 56, 68, 82]
    rvals = np.array([int(val) * 10**e for val in stdvals for e in range(0, 8)])
else:
    rvals = np.array([round(10.**(i/96.),2) * 10**e for i in range(96) for e in range(1,9)], dtype=int)
nearest=lambda vals,a: min(vals, key=lambda x:abs(x-a))

limitedvals = rvals[rvals <= target]
possiblefirst = limitedvals[limitedvals >= target/2]
options = []
for p in possiblefirst:
    possiblesecond = limitedvals[limitedvals<(target-p)]
    if len(possiblesecond) == 0:
        possiblesecond = [0]
    bestsecond = nearest(possiblesecond,target-p)
    options = options + [[p,bestsecond,target-(p+bestsecond)]]

optarr = np.array(options)
minerr = np.min(np.abs(optarr[:,2]))
bestoptions = optarr[optarr[:,2] == minerr]
bestoptions = np.array(bestoptions, dtype=np.float64) / 100
for option in bestoptions:
    print("%.1f + %.1f = %.1f (error: %.1f/%.2f%%)" % (option[0], option[1], option[0]+option[1], option[2], abs(100*option[2]/float(option[0]+option[1]))))