28 May 2009 2:59:48.803 PM PIECEWISE_LINEAR_PRODUCT_INTEGRAL_PRB FORTRAN77 version TEST01 Test PIECEWISE_LINEAR_PRODUCT_INTEGRAL on a very simple problem. F and G are both defined over a single common interval, so that F(X) = G(X) = X. A B Integral Exact 1.0000 1.0000 0.00000 0.00000 1.0000 2.0000 2.33333 2.33333 1.0000 3.0000 8.66667 8.66667 1.0000 4.0000 21.0000 21.0000 1.0000 5.0000 41.3333 41.3333 TEST02 Test PIECEWISE_LINEAR_PRODUCT_INTEGRAL on a simple problem. F and G are both defined over separate, multiple intervals, but still true that F(X) = G(X) = X. A B Integral Exact 1.0000 1.0000 0.00000 0.00000 1.0000 2.0000 2.33333 2.33333 1.0000 3.0000 8.66667 8.66667 1.0000 4.0000 21.0000 21.0000 1.0000 5.0000 41.3333 41.3333 TEST03 Test PIECEWISE_LINEAR_PRODUCT_INTEGRAL on a simple problem. F and G are defined over separate, multiple intervals. F(X) interpolates SIN(X), G(X) interpolates 2*COS(X). We compare: INTEGRAL, our value for the integral, QUAD, a quadrature estimate for the integral, and CLOSE, the value of the integral of 2*COS(X)*SIN(X) A B Integral Quad Close 0.0000 0.0000 0.00000 0.00000 -0.00000 0.0000 0.5236 0.247447 0.247447 0.250000 0.0000 1.0472 0.743259 0.743259 0.750000 0.0000 1.5708 0.990786 0.990786 1.00000 0.0000 2.0944 0.743259 0.743259 0.750000 0.0000 2.6180 0.247447 0.247447 0.250000 0.0000 3.1416 -0.256739E-14 0.423652E-15 -0.00000 TEST04 Test PIECEWISE_LINEAR_PRODUCT_INTEGRAL. The nodes are at 0, 1, and 2. F(X) = ( 0, 1, 0 ). G(X) = ( 1, 0, 0 ). Integral F(X) * F(X) dx = 0.666667 Integral F(X) * G(X) dx = 0.166667 Integral G(X) * G(X) dx = 0.333333 PIECEWISE_LINEAR_PRODUCT_INTEGRAL_PRB Normal end of execution. 28 May 2009 2:59:48.809 PM