DOE-2 Reference Manual Version 2.1 - DOE2.com

DATAQUADRATIC means that if the data are given with the DATA keyword,they are to be fit to a quadratic equation with onedependent variable, z, and one independent variable, x, of theform Z = a + bx + cx 2 . If the data are given with theCOEFFICIENTS keyword, they will be treated as coefficients ofthe equation. The curve is represented graphically by aparabola (or half-parabola). The coefficients are a, b, and c.BI-QUADRATIC means that if the data that follow are given withthe DATA keyword, they will be fit to a bi-quadratic equationin which there is one dependent variable, z, and there are twoindependent variables, x and y. If the data are given with theCOEFFICIENTS keyword, they will be treated as coefficients ofthe equation. The curve has the form Z = a + bx + cx2 + dy +ey2 + fxy. It is represented graphically by a curved surface.The coefficients are a through f.CUBIC means that if the data that follow are given with theDATA keyword, they will be fit to a cubic equation in whichthere is one dependent variable, z, and one independentvariable x. If the data are given with the COEFFICIENTSkeyword, they will be treated as coefficients of the equation.The curve has the form Z = a + bx + cx2 + dx 3 and may berepresented graphically by a curve with one inflection point, amaximum, and a minimum. The coefficients are a through d.will be followed by up to 20 sets of values. If TYPE = LINEAR,QUADRATIC, or CUBIC, each set will contain two values in theorder (independent varlable, dependent variable), or (x,z). IfTYPE = BI-LINEAR or BI-QUADRATIC, each set will contain threevalues in the order (independent-varlable-l, independentvariable-2,dependent-variable), or (x,y,z). If TYPE = LINEAR,at least two points (two lists of coordinate values) must beinput. If TYPE = BI-LINEAR or QUADRATIC, at least three points(three lists of values) must be provided. Note that to input aplane, the three points must not all be on the same line. Forexample, (1,1), (3,3), and (6,6) define a line but not a plane;(1,1), (3,3), and (6,4) define a plane. When only threecoordinate sets are input to define a quadratic, the bestaccuracy will be achieved if two of the points (pairs ofcoordinates) lie at either end of the user's range of interest,and the third lies between them, at the approximate maximum orminimum if the curve increases and decreases (see Fig. IV.18).IV.182 (Revised 5/81)