cannot find existing number

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Luis Eduardo Cofré Lizama
评论： Star Strider 2023-1-8
I have the following data where fs =100;
tstamp =(1/fs:1/fs:12000*(1/fs))
Then when looking for the value 117 (find(tstamp == 117)), the results is [], however, the value does exist though with a trail of zeros (117.0000), is that the prob? how to solve?
Please help with this very likely simple prob.
cheers
Eduardo

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Star Strider
Star Strider 2023-1-8
Ran in:
See the documentation section on Floating-Point Numbers for a full explanation.
Actually, I can’t reproduce that exact problem, since it works correctly here —
format long
fs =100;
tstamp =(1/fs:1/fs:12000*(1/fs))
tstamp = 1×12000
0.010000000000000 0.020000000000000 0.030000000000000 0.040000000000000 0.050000000000000 0.060000000000000 0.070000000000000 0.080000000000000 0.090000000000000 0.100000000000000 0.110000000000000 0.120000000000000 0.130000000000000 0.140000000000000 0.150000000000000 0.160000000000000 0.170000000000000 0.180000000000000 0.190000000000000 0.200000000000000 0.210000000000000 0.220000000000000 0.230000000000000 0.240000000000000 0.250000000000000 0.260000000000000 0.270000000000000 0.280000000000000 0.290000000000000 0.300000000000000
v = find(tstamp == 117)
v =
11700
D = v - 11700
D =
0
I was hoping to be able to demonstrate floating-point approximation error.
Oh well ...
.
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Walter Roberson
Walter Roberson 2023-1-8
There are various fairly obscure ways in which the floating point round-off algorithm can end up being changed. That does not happen often, but it can happen.

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Walter Roberson
Walter Roberson 2023-1-8

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