CoCoA » CoCoA-5

• a global flag which says what the default verbosity is
• an optional arg to calls to Normaliz which indicates the verbosity for that call

Where are verbose messages printed? Presumably on whatever output stream CoCoA-5 is using.

• just 2? in which case we could use a boolean
• more than 2? in which case we should probably use a (non-negative) integer

Christof says that Normaliz uses a bool.

Should CoCoALib simply follow what Normaliz does for its normaliz related flags?
And follow what Frobby does for its frobby related flags?
etc?

Let's get this sorted out for 5.1.4!

The cone object in cocoalib has a SetVerbose method. But that is not so useful from cocoa5 since we don't have an object there.

There is also the possibility to set the global verbose default value which is useful from c5 and I already implemented NmzSetVerboseDefault as a one-line built-in function. It is even documented and is working!

One point needs improvement: The output is written to std::cout. This can be changed with the libnormaliz functions

void setVerboseOutput(std::ostream&);
void setErrorOutput(std::ostream&);

should we call it NmzSetVerbosityLevel?

If the behaviour from the point of view of a user is similar to that of CoCoA's own SetVerbosityLevel then it would make sense to give it a similar name. Presumably there would be just two levels: 0 and 1 (or anything positive).

I think there may be a subtle difference for a CoCoALib user: if I recall well, each cone may have its own "verbosity" setting (but the default value is taken from the system/global setting.

John Abbott wrote:

If the behaviour from the point of view of a user is similar to that of CoCoA's own SetVerbosityLevel then it would make sense to give it a similar name. Presumably there would be just two levels: 0 and 1 (or anything positive).

In view of doing something similar for other external libraries, I propose the general rule
- XxxSetVerbosityLevel/XxxVerbosityLevel
- levels 0 and 10 (and above)
(as we say that values 1..9 are reserved for the users)

I think there may be a subtle difference for a CoCoALib user: if I recall well, each cone may have its own "verbosity" setting (but the default value is taken from the system/global setting.

Then we say in the documentation that these functions are for the default levels.

Currently Normaliz has just two verbosity levels (true and false).
There is not much problem in saying that numerical levels below 10 correspond to false, an higher levels correspond to true. BUT what happens if Normaliz also decides to have several numerical levels of verbosity? For instance, they may have levels 0-5 inclusive. How do we map those numerical levels to CoCoA?

John Abbott wrote:

Currently Normaliz has just two verbosity levels (true and false).
There is not much problem in saying that numerical levels below 10 correspond to false, an higher levels correspond to true. BUT what happens if Normaliz also decides to have several numerical levels of verbosity? For instance, they may have levels 0-5 inclusive. How do we map those numerical levels to CoCoA?

as you wish, the important thing for me is the names: I don't want to confuse users with different kindof names when we are just advertising the new feature.

OK for the names XXXSetVerbosityLevel and XXXVerbosityLevel where XXX could be Nmz or some other prefix for an external library.

I would like to consult briefly with the Normaliz people what they would like to have, since I expect they will be the main users of "verbosity" for Normaliz. I'm not sure if any of the other external libraries has a verbosity setting.

Winfried, we would like to use non-negative integers to indicate verbosity levels (where higher numbers trigger printing of more information, up to some limit). Currently, all built-in CoCoA commands produce no "verbose" output with a setting below 10... this allows users to employ values up to 9 for their own code.

I would like to have separate verbosity levels for CoCoALib and for "external libraries" (such as Normaliz).

• (A) use levels 0 and 1 for Normaliz
• (B) use levels 0 and 10 (or some higher threshold) for Normaliz

In either case, a setting below the threshold would correspond to Normaliz verbosity false, and any setting greater than or equal to the threshold would correspond to true (unless/until Normaliz employs more than 2 levels of verbosity).

No CoCoA function should produce any "verbose output" just because NmzVerbosityLevel is positive; in other words, the CoCoA verbosity setting anf the Normaliz one are completely independent.

Comments?

Normaliz has only two levels of verbosity: off or on. Via libnormaliz this can be toggled. I think the CoCoA interface to Normaliz then needs a function that switches verbose on or off for Normaliz.

I have thought about introducing three levels of verbosity: off, the most important steps, everything. But this has really low priority.

Done.
Two functions (4 in cocoalib, for default and for cone): NmzSetVerbosityLevel/NmzVerbosityLevel, as in cocoa/cocoalib behaviour.
NmzSetVerbosityLevel takes an INT but for now converts 0 to off, and >0 to on.
Documented.
Close?

Winfried Bruns wrote:

I have thought about introducing three levels of verbosity: off, the most important steps, everything. But this has really low priority.

This confirms it has been a good idea to have the Normaliz verbosity implementation in CoCoALib accepting INT (as for the CoCoA verbosity implementation).