Re: Converting decimal number to carpenter's fractions
- Posted by ne1uno May 05, 2012
- 2980 views
K_D_R said...
Does anyone have, or can recommend a routine to convert decimals to carpenters inch fractions: 32nds, 16ths, 8ths, 4ths, halfs? I have a list of equivalents so I guess If there is no exact match, I would need to compare up the list until a higher value is reached and then subtract my search value from the larger value and subtract the previous lower value from the decimal value I am seeking to convert and then select the value which has the lowest difference.
sequence decimal_fractions { {.03125, 1, 32}, {.06250, 1, 16}, {.09375, 3, 32}, ..... {.96875, 31, 32} x = 0.07356 0.09375 - 0.07356 = 0.02019 0.07356 - 0.06250 = 0.01106 x = {1,16} or 1/16th inch
Seems like there must be an easier way, though.
Any suggestions would be appreciated.
I've used something like this
-- minimum fraction default 1/64th -- needs more work if want to find the nearest fraction over or under. -- might be nice to return the amount over if any. -- public function dec_frac(atom x1, atom minfraction = 0.015625) atom numerator = 1, denominator = 2, mf = 64 x1 += 0.00002 if minfraction < 1 then mf = floor(math:abs(1/minfraction)) end if for r = numerator to mf - 1 do if abs(x1 - (r/mf)) <= minfraction then numerator = r goto "done" end if end for return {} --error label "done" --simplity return {numerator/math:gcd(numerator, mf) , mf/math:gcd(numerator, mf)} end function test_equal("dec_frac 1/32",{1,32}, trig:dec_frac(1/32)) test_equal("dec_frac 1/16",{1,16}, trig:dec_frac(1/16)) test_equal("dec_frac 3/32",{3,32}, trig:dec_frac(.094)) test_equal("dec_frac 1/4",{1,4}, trig:dec_frac(0.25)) test_equal("dec_frac 5/8",{5,8}, trig:dec_frac(0.625)) test_equal("dec_frac 7mm",{17,64}, trig:dec_frac(0.2756))
