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Floor | <. 0 0 0 | Lesser Of (Min)

`<.y` gives the floor of`y` ,`` that is, the largest integer less than or equal to`y` .`` Thus:

       <. 4.6 4 _4 _4.6
    4 4 _4 _5

The implied comparison with integers is tolerant, as discussed under Equal (`=`), and is controlled by`<.!.t` .`` See below for complex arguments.

`x<.y` is the lesser of`x` and`y` .`` For example:

       3 <. 4 _4
    3 _4

       <./7 8 5 9 2
    2

       <./\7 8 5 9 2
    7 7 5 5 2

For a complex argument, the definition of`<.` is modelled by:

       floor=: j./@(ip+(c2>c1),c1+:c2)
       '`c1 c2 fp ip'=:(1:>+/@fp)`(>:/@fp)`(+.-ip)`(<.@+.)

As developed by McDonnell [10], this function has the following properties:

Convexity: | If`(<.z1)=(<.z2)` and`z3` lies on the line between`z1` to`z2`,`` then`(<z3)=(<z1)`.
Translatability: | If`z4` is a Gaussian integer, then`(z4+<.z5)=(<.z4+z5)`.
Compatibility: | `(<.x j.0)=((<.x)j.0)` and`(<.0 j.x)=(0 j.(<.x))`

The function`<.` can be viewed as a tiling by rectangles of unit area, all arguments within a rectangle sharing the same floor. One rectangle has vertices at`1j0` and`0j1`,`` with the other side passing through the origin. Rectangles along successive diagonals are displaced by one-half the length.
The phrase`j./@ip` “floors” the individual parts of a complex argument. Moreover, the floor`<.y` is equivalent to`->.-y` . In other words, it is the dual of ceiling with respect to (that is, under) arithmetic negation:`<.` ↔`>.&.-` and`>.` ↔`<.&.-` . Thus:

       (>.&.- ; <.) 4.6 4 _4 _4.6
    +---------+---------+
    |4 4 _4 _5|4 4 _4 _5|
    +---------+---------+

The expression`<.x+0.5` gives the integer nearest to the real argument`x`,`` and`<.z+0.5j0.5` gives the Gaussian integer nearest to`z`. The number of digits needed to represent an integer is given by one plus the floor of its base ten logarithm:

       a ,. (,. 1:+<.) 10^. a=: 9 10 11 99 100 101
      9 0.954243 1
     10        1 2
     11  1.04139 2
     99  1.99564 2
    100        2 3
    101  2.00432 3

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