Use of "-wise" in phrases or words

Solution 1:

The question you referred to in yours gives more usage notes on when you should use the "-wise" suffix, but not so much in terms of what it means. In this case, "wise" is supposed to serve as a suffix which means:

with reference to: profitwise ; businesswise

The example you quoted would be less ambiguous if they had used "computation-wise". (Computational-wise seems ungrammatical to me). That is, the sentence is saying that:

Floor is obscenely expensive [in terms of] computation

or,

Floor is obscenely expensive computationally

Solution 2:

To quote a different source from the cited question, I'll use Dictionary.com:

a suffixal use of wise - in adverbs denoting manner, position, direction, reference, etc.: counterclockwise; edgewise; marketwise; timewise.

To simplify this definition, you can think of -wise as "in the direction of", "in the manner of" or "with regard to", depending on the situation.

The sentence you provided falls obviously in the third case.

Solution 3:

Clockwise means in relation to a clock.

Floor is obscenely expensive computational wise.

It's not a very well written sentence, but it means the "floor" operation is obscenely expensive in relation to computation.