I've noticed that using a non-integer index on a vector returns a value. For example, if I set
x = 1:5;
y = x[{1.2 5.7}];
then y returns a 2-vector {1, 5}.
It seems that the indexes are having the floor function applied before being used to find elements of x. Is this correct?
My experiment indicates that there is some fuzzing as well, so that x[1-epsilon] still returns x[1]:
x=1:5;
i = 2 - 10##-T(11:16);
y = x;
print i[format=20.16] y;
Isn't that what we'd expect from the floor function? Anything less than 2 (even if just epsilon) is 1?
Add this to the end of the previous program:
f = floor(i);
print i[format=20.16] f y;
You'll see that the conversion of noninteger subscripts is different from a simple floor. The fuzzing of near-integer values is important to correctly handle floating point arithmetic. If you reread my previous post, you'll see that I stated that x[1-epsilon] = x[1], not x[0] (which would be an error).
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