Improve verbose messages in rolling functions

[jangorecki]

• verbose message should be more user friendly

Main reason behind adding verbose output for rolling functions was to track which code paths they are being computed. As a result messages where not much user friendly, and 0 and 1 were used where names could be used instead.

Rather than

frolladaptivefun: algo 0 not implemented, fall back to 1

We should produce

frolladaptivefun: algo fast not implemented, fall back to exact

Also instead of

frollfun: processing fun 0 algo 0 took...

We should produce

frollfun: processing fun mean algo fast took...

• tweak use of snprintf() for verbose messages

The idiom 1) should be more like 2) but I don't see a way the current code could overflow the 4096-byte buffer, even with long translation strings; the current code doesn't cause a problem.

snprintf(end(message), 500, format, ...)

len = strlen(ans->message[0])
snprintf(ans->message[0] + len, sizeof(ans->message[0]) - len, format, ...)

Filling out this issue to not forget.
As this is not a high priority, it is postponed till rolling functions related PRs are merged, to reduce work needed to resolve merge conflicts.

[aidengseay]

I am part of a group in Igor's open source software class at Northern Arizona University, and my group is interested in completing this issue. We got it from a list from issue #7649.

[aidengseay]

My group has a solution for this issue. We made a poor attempt at a pull request here. Wanted to add it to this issue for continuity. We will reattempt, but if we don't hear anything in two weeks, please assign the issue to someone else.