# krawczykMethodOptions -- invertible matrix for computing Krawczyk operator (option for "krawczykOper" and "krawczykMethod")

## Description

 i1 : options krawczykMethod o1 = OptionTable{InvertibleMatrix => null} o1 : OptionTable

This is an option for krawczykOper and krawczykMethod. By default, these functions uses the inverse of the matrix obtained by evaluating the system at the midpoint of the input interval.

Input for this option have to be an invertible matrix.

 i2 : R = QQ[x1,x2,y1,y2]; i3 : f = polySystem {3*y1 + 2*y2 -1, 3*x1 + 2*x2 -7/2,x1^2 + y1^2 -1, x2^2 + y2^2 - 1}; i4 : (I1, I2, I3, I4) = (interval(.94,.96), interval(.31,.33), interval(-.31,-.29), interval(.94,.96)); i5 : o = intervalOptionList {("x1" => "I1"), ("x2" => "I2"), ("y1" => "I3"), ("y2" => "I4")}; i6 : Y = matrix {{.095, .032, .476, -.100},{-.143, .452, -.714, .150},{.301,.101,-.160, -.317},{.048,-.152,.240,.476}}; 4 4 o6 : Matrix RR <--- RR 53 53 i7 : krawczykMethod(f,o,InvertibleMatrix => Y) o7 = true

## For the programmer

The object krawczykMethodOptions is .