你好，
我正在绘制一系列不同的设备及其信号响应响应作为时间的函数。 一旦绘图超过一个值，例如 3100，我希望从每个更平滑的绘图中提取时间值。 散射数据太粗略，无法获得发生这种情况的时间，但是如果每个设备的平滑拟合背后都有一个函数，那么这个信息应该是可用的。
有谁知道这是否可行，如果可以，如何完成？
JMP 确实提供了功能样条系数（）和样条评估（） .您可以使用样条系数（）获取样条参数，然后在任何所需点评估该样条。您可以轻松地将其与牛顿法一起使用来确定每个样条何时穿过某个值（例如 3100）。
请注意，您需要在此之前标准化 x 数据（零均值，std-dev = 1），以便样条 lambda 可以匹配您通常期望的值。
这是我刚刚汇总的一个示例，我相信它可以满足您的要求：
Names Default to Here( 1 );
determine crossover = Function( {table, value, spline lambda, x col, y col, group, precision = 0.1},
{Default Local},
spline number = 64;
max runs = 10;
rows = table << Get Rows Where( Excluded( Row State() ) == 0 );
groups = Associative Array( Column( table, group )[rows] ) << Get Keys;
curves = [=>];
For( i = 1, i <= N Items( groups ), i++,
item = groups[i];
Eval( Parse( Eval Insert( JSL Quote(
rows = table << Get Rows Where( Excluded( Row State() ) == 0 & :Name("^group^") == "^item^" )
) ) ) );
curves[item] = [=>];
curves[item]["rows"] = rows;
curves[item]["abcissa"] = Column( table, x col )[rows];
curves[item]["ordinate"] = Column( table, y col )[rows];
curves[item]["abcissa mean"] = Mean( curves[item]["abcissa"] );
curves[item]["abcissa stddev"] = Std Dev( curves[item]["abcissa"] );
If( curves[item]["abcissa stddev"] == 0, curves[item]["abcissa"] = 1 );
curves[item]["abcissa"] = (curves[item]["abcissa"] - curves[item]["abcissa mean"]) / curves[item]["abcissa stddev"];
first = Min( curves[item]["abcissa"] );
last = Max( curves[item]["abcissa"] );
curves[item]["crossover abcissa"] = .;
curves[item]["crossover ordinate"] = -1932870987120;
run = 1;
While( Abs( value - curves[item]["crossover ordinate"] ) > precision * value & run <= max runs,
run++;
points = first :: last :: (last - first) / spline number;
coef = Spline Coef( curves[item]["abcissa"], curves[item]["ordinate"], spline lambda );
spline = Spline Eval(
points,
coef
);
For( j = 1, j <= spline number, j++,
If( spline[j] > value,
first = If( j == 1, first, points[j - 1] );
last = points[j];
Break();
,
If( Abs( value - spline[j] ) < Abs( value - curves[item]["crossover ordinate"] ),
curves[item]["crossover abcissa"] = points[j] * curves[item]["abcissa stddev"] + curves[item]["abcissa mean"];
curves[item]["crossover ordinate"] = spline[j];
)
)
);
If( first == last, Break() );
);
first = Min( curves[item]["abcissa"] );
last = Max( curves[item]["abcissa"] );
points = first :: last :: (last - first) / spline number;
curves[item]["spline ordniate"] = Spline Eval(
points,
coef
);
curves[item]["spline abcissa"] = points * curves[item]["abcissa stddev"] + curves[item]["abcissa mean"];
curves[item]["abcissa"] = curves[item]["abcissa"] * curves[item]["abcissa stddev"] + curves[item]["abcissa mean"];
);
curves
);
dt = Open("$SAMPLE_DATA/Nonlinear Examples/Algae Mitscherlich.jmp");
lambda = 1;
Current Data Table( dt );
gb = Graph Builder(
Size( 516, 450 ),
Show Control Panel( 0 ),
Variables( X( :Days ), Y( :Algae density ), Overlay( :Treatment ) ),
Elements( Points( X, Y, Legend( 18 ) ), Smoother( X, Y, Legend( 19 ), Lambda( lambda ) ) ),
SendToReport(
Dispatch(
{},
"Algae density",
ScaleBox,
{Add Ref Line( 3, "Solid", "Black", "", 1 )}
)
)
);
curves = determine crossover( dt, 3, lambda, "Days", "Algae density", "Treatment", 0.001 );
gbr = Report( gb );
dt << Color or Mark by Column( :Treatment );
{y min, y max} = Eval List( {gbr[Axis Box( 2 )] << Get Min, gbr[Axis Box( 2 )] << Get Max} );
key = curves << First;
While( !Is Empty( key ),
Print( Eval List( {key, curves[key]["crossover abcissa"], curves[key]["crossover ordinate"]} ) );
color = Color Of( Row State( curves[key]["rows"][1] ) );
Eval( Eval Expr(
gbr[Frame Box( 1 )] << Add Graphics Script(
Pen Color( Expr( color ) );
Pen Size( 2 );
Line( {Expr( curves[key]["crossover abcissa"] ), Expr( y min )}, {Expr( curves[key]["crossover abcissa"] ), Expr( y max )} )
)
) );
key = curves << Next( key )
)
JMP Pro 中的函数数据资源管理器提供了许多用于处理函数、轮廓和曲线的工具。
