This procedure is based on the interval evaluation of equations using
centered form with as centers two possible centers which may be
optimal (see the `ALIAS` C++ manual for the calculation of these
centers). The centered form uses the fact the interval evaluation of a
function in the unknown
is included in
where is point called the center. As mentioned
earlier two possible centers are calculated. Furthermore the
calculation of the product may involve several occurrences
of the same variables, that are not detected when computing the
product numerically. This procedure allows, as an option, to compute
symbolically the product and to re-arrange it in order to try to
reduce multiple occurrences.

The syntax of this procedure is:

BiCenteredForm(func,funcproc,Jfuncproc,vars,custom,procname)where

`func`: a list of equations`funcproc`: the name of a procedure in`MakeF`format that computes the interval evaluation of`func``Jfuncproc`:the name of a procedure in`MakeJ`format that computes the interval evaluation of the derivatives of`func``vars`: a list of variable names`custom`: a string that indicate how`funcproc`and`Jfuncproc`are obtained.`"none"`: the procedure will assume that funcproc and Jfuncproc are the procedures`F`and`J`that are generated by`GradientSolve`and`HessianSolve``"F"`: the procedure will assume that`funcproc`is a customized procedure that, for example, has been generated by`MakeF``"J"`: the procedure will assume that`Jfuncproc`is a customized procedure that, for example, has been generated by`MakeJ``"FJ"`: the procedure will assume that`funcproc`and`Jfuncproc`are customized procedures

`procname`: the name of the simplification procedure that will be created in the file`procname.C`