RosettaCodeData/Task/Van-der-Corput-sequence/Jq/van-der-corput-sequence-1.jq
2017-09-25 22:28:19 +02:00

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# vdc(base) converts an input decimal integer to a decimal number based on the van der
# Corput sequence using base 'base', e.g. (4 | vdc(2)) is 0.125.
#
def vdc(base):
# The helper function converts a stream of residuals to a decimal,
# e.g. if base is 2, then decimalize( (0,0,1) ) yields 0.125
def decimalize(stream):
reduce stream as $d # state: [accumulator, power]
( [0, 1/base];
.[1] as $power | [ .[0] + ($d * $power), $power / base] )
| .[0];
if . == 0 then 0
else decimalize(recurse( if . == 0 then empty else ./base | floor end ) % base)
end ;