Port the feasible circulation algorithm

[Alpar Juttner]

This ticket is a follow-up of #47.

The affected files are

• lemon/circulation.h

This ticket depends on #174.

[Alpar Juttner]

The attached bundle file​ ports the Circulation class. Namely,

• [5a7dbeaed70e] ports the files plus does the usual basic trimming.
• [a26cb20c4c5f] turns the demo code into a test.
• [ef7c87032593] changes Def* to Set*.

[Peter Kovacs]

I attached two changesets containing improvements. See [b4fbf36feb57] and [2a7704daaf11].

Make check fails on [ef7c87032593] because of a missing #include. [2a7704daaf11] also fixes this.

[Peter Kovacs]

I have two questions:

1. What concept do we want to follow about "checker funtions" like the ones in Circulation? Most of the algorithms do not contain such functions, only the test files of them. Should such checker function be placed into the algorithm classes or into the test files? An end-user typically don't need such checking since the correctness of the algorithms should be supposed. (Among others that's why we have test files.)

2. How should a test file read the input graph? From a separate file or from a constant char array? See e.g. preflow_test.cc and circulation_test.cc.

[Alpar Juttner]

Replying to kpeter:

Make check fails on [ef7c87032593] because of a missing #include. [2a7704daaf11] also fixes this.

Very strange. I'm pretty sure I tried to compile it. (If not, then it is actually quite impressive that the missing include is the only error I made, isn't it? :) )

Btw, why do we need to include the lemon/elevator.h? Isn't is included by lemon/circulation.h?

[Peter Kovacs]

Replying to alpar:

Btw, why do we need to include the lemon/elevator.h? Isn't is included by lemon/circulation.h?

Yes, this include is unnecessary. I just copied the #include commands from preflow_test.cc which also contains this unnecessary line.

You can remove it from both test files.

[Peter Kovacs]

For this test file you can use [63c4cc72d7eb] isntead of the former changeset.

[Alpar Juttner]

A bit reorganized version of these changes are in the main now, see [5a7dbeaed70e], [fa341dd6ab23], [26fd85a3087e], [235be9d4b6ab] and [940587667b47].