Context Navigation

Changes between Initial Version and Version 1 of Ticket #4630, comment 3

initial	v1
15	15	being transformed to
16	16	{{{
17		a*b = log(f(c))
	17	a+b = log(f(c))
18	18	}}}
19	19	or vice-versa. The two equations are equivalent from a mathematical point of view; however, the residual of the first is always well-defined, while the residual of the second can only be computed if f(c) > 0, which could be problematic for a numerical solver if c is selected as a tearing variable. Another example is reported in #4293