- local delta = 0.05 // 步长
- local x = 1 // x 的初始值
- local j = 0 // 计数器:记录迭代次数
- local e = 1 // y1-y0
- local e0 = 0.01 // 收敛判据 (精度判据)
- while `e' > `e0'{
- `trace'
- local y0 = 0.2*exp(`x') - ln(`x'^2) + 3
- local x = `x' + `delta'
- local y1 = (0.2*exp(`x') - ln(`x'^2)) + 3
- local e = abs(`y1' - `y0') //abs:绝对值函数的简写
- dis in g "*" _c
- local j = `j' + 1
- }
- dis "e = " `e'
- dis "x = " `x' // x 的解
- dis "y = " `y1' // y 的极小值
- dis "j = " `j' // 迭代次数
-
- *-图示:
- twoway function y = 0.2*exp(x) - ln(x^2) + 3, ///
- range(0 4) lw(thick) xline(`x') yline(`y1') ///
- text(`=`y1'-0.5' `=`x'+0.8' "(`x',`y1')")


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