piecewise_eval

代码说明：

  LINEINTRGAL Line Integral in a 2D Vector Field. LINEINTRGAL(X,Y,U,V,C) computes the line integral along the lines given in cell array C. X and Y define the coordinates of a rectangular grid over which U and V are defined. X and Y must be monotonic and 2D plaid as ％ produced by MESHGRID. X, Y, U, and V must all be the same size.(LINEINTRGAL Line Integral in a 2D Vector-Fi eld. LINEINTRGAL (X, Y, U, V, C) computes the line integral along the lines gi ven in cell array C. X and Y coordinate define the s of a rectangular grid over which U and V are defi ned. X and Y must be monotonic and 2D plaid% as pro duced by MESHGRID. X, Y, U, and V must all be the same size.)