slib_title=Double entry table for training to relations between three quantities
slib_parms=7\
(I,A,1,10,z/y,(x-1)*(10-x)), A 5- or 6-uple of metadata for X: symbol_x, unit_x, min_x, max_x, formula_x, optional valid_x (this expression will be constrained to be positive) \
(R,Ohm,1,10,z/x,(y-1)*(10-y)), A 5- or 6-uple of metadata for Y: symbol_y, unit_y, min_y, max_y, formula_y, optional valid_y (this expression will be constrained to be positive) \
(U,V,1,100,x*y,(z-1)*(100-z)), A 5- or 6-uple of metadata for Z: symbol_z, unit_z, min_z, max_z, formula_z, optional valid_z (this expression will be constrained to be positive) \
3, nl (number of lines of the table, nl >=2) \
3, nc (number of columns of the table, nc >=2)\
3, precision (number of significative digits)\
0, debug (debug=1 enables the pre-filling of the table fields with correct replies, it may be useful for Modtool exercises)

slib_out=One table with input fields, 
the number NR of replies, 
the list of the NR replies, 
the list of the (NR+1) chunks of table to be interleaved with \embed{} in the statement of an OEF exercise.
slib_comment=This library requires Pari/GP ; it features training about a relation between three quantities, like the Ohm law: U=R*I, I=U/R, R=U/I. 
X refers to the first variable, Y to the second and Z to the third.