r2D</a></strong>(double&nbsp;a1,
        <a href="../../../../../../../../org/apache/commons/math3/geometry/euclidean/twod/Vector2D.html" title="class in org.apache.commons.math3.geometry.euclidean.twod">Vector2D</a>&nbsp;u1,
        double&nbsp;a2,
        <a href="../../../../../../../../org/apache/commons/math3/geometry/euclidean/twod/Vector2D.html" title="class in org.apache.commons.math3.geometry.euclidean.twod">Vector2D</a>&nbsp;u2)</code>
<div class="block">Linear constructor
 Build a vector from two