integ1 X-Function is capable of finding the area under a curve using integration. Both mathematical and absolute areas can be computed. In the following example, the absolute area is calculated:
The//Import a sample data newbook; fname$ = system.path.program$ + "Samples\Mathematics\Sine Curve.dat"; impasc; //Calculate the absolute area of the curve and plot the integral curve integ1 iy:=col(2) type:=abs plot:=1;
Once the integration is performed, the results can be obtained from the integ1 tree variable:
// Dump the integ1 tree integ1.=; // Get a specific value double area = integ1.area;
The X-Function also allows specifying variable names for quantities of interest, such as:
double myarea, ymax, xmax; integ1 iy:=col(2) type:=abs plot:=1 area:=myarea y0:=ymax x0:=xmax; type "area=$(myarea) %(CRLF)ymax=$(ymax) %(CRLF)xmax=$(xmax)";
Integration of two-dimensional data in a matrix can also be performed using the integ2 X-Function. This X-Function computes the volume beneath the surface defined by the matrix, with respect to the z=0 plane.
// Perform volume integration of 1st matrix object in first matrixsheet range rmat=[MBook1]1!1; integ2 im:=rmat integral:=myresult; type "Volume integration result: $(myresult)";