gnuplot:范围内的最大值和最小值 [英] gnuplot: max and min values in a range

问题描述

我正在绘制一些具有不同X范围的数据，我想根据当前X范围内数据的最大值和最小值更改yrange.当我使用GPVAL_Y_MAX和GPVAL_Y_MIN时，这些值对应于整个数据的最大值和最小值，而不仅仅是范围内的数据.

I'm plotting some data with a different X range and I would like to change yrange according to the maximum and minimum value of the data in the current X range. When I use GPVAL_Y_MAX and GPVAL_Y_MIN, these values correspond to the maximum and minimum of the whole data, not just the data in the range.

例如，我有以下数据:

1 3
2 5
3 8
4 20
5 30

我使用以下脚本:

plot 'data.txt' u 1:2;
set xrange [1:3];
replot
set xrange [1:5];
replot

在第一个情节中，我想在[3:8]中设置yrange，但是在第二个情节中，yrange应当为[3:30].如果我使用类似的东西

In the first plot I would like to set yrange in [3:8], but in the second plot the yrange sholud be [3:30]. If I use something like

set yrange [GPVAL_Y_MIN:GPVAL_Y_MAX]

GPVAL_Y_MIN和GPVAL_Y_MAX具有相同的值，而与xrange无关.

GPVAL_Y_MIN and GPVAL_Y_MAX have the same value independently of the xrange.

有解决方案吗?

推荐答案

所需的变量是GPVAL_DATA_Y_MIN和GPVAL_DATA_Y_MAX，它们是在特定范围内绘制的数据的y-min/max. GPVAL_Y_MIN和GPVAL_Y_MAX通常不太有用，因为它们告诉您绘图边框的边缘在哪里(通常，这些值超出了GPVAL_DATA...变量的范围，因为gnuplot在数据和图的边缘).

The variables you want are GPVAL_DATA_Y_MIN and GPVAL_DATA_Y_MAX, which are the y-min/max of the data plotted in a certain range. GPVAL_Y_MIN and GPVAL_Y_MAX are a little less useful generally because they tell you where the edges of the plot border are (in general these values extend a little beyond the GPVAL_DATA... variables because gnuplot leaves a little space between the data and the edge of the plot).

要利用这些变量，必须对plot命令使用范围说明符:

To take advantage of these variables you have to use the range specifiers to the plot command:

plot [1:3] 'data.txt'
set yr [GPVAL_DATA_Y_MIN:GPVAL_DATA_Y_MAX]
replot
...

顺便说一句，除非您想提醒自己要绘制的列，否则u 1:2规范是多余的，因为将前两列分别绘制为x和y是gnuplot的默认设置.如果您不想重新绘制到相同的输出端子(在像eps这样的某些端子中没有帮助，在该端子上重新绘制将以相同的图形绘制第二页)，请使用以下命令序列:

By the way, the u 1:2 specification is redundant unless you want to remind yourself of which columns you are plotting, since plotting the first two columns as x and y is the gnuplot default. If you don't want to replot to the same output terminal (which is not helpful in some terminals like eps where replotting makes a second page with the same plot), use this command sequence:

set terminal unknown
plot [1:3] 'data.txt'
set terminal <actual output terminal here>
set output 'output.trm'
plot [1:3][GPVAL_DATA_Y_MIN:GPVAL_DATA_Y_MAX] 'data.txt'

请再次注意使用范围说明符，这一次指定了y范围.这比用set yrange指定要紧凑一些，但是需要更长的代码行.

Note the use of the range specifier again, this time with a y range specified. This is a little more compact than specifying with set yrange, but makes for a longer line of code.

如果您具有gnuplot 4.6.0或更高版本，则可以利用stats命令来避免重新配置. stats命令创建了一堆方便的变量

If you have gnuplot 4.6.0 or higher, you can take advantage of the stats command to avoid replotting. The stats command creates a bunch of handy variables

stats [1:3] 'data.txt'
plot [1:3][stats_min_y:stats_max_y] 'data.txt'

一个稍微不同的命令，

stats [1:3] 'data.txt'
plot [stats_min_x:stats_max_x][stats_min_y:stats_max_y] 'data.txt'

将基于实际数据所在的位置在x方向上填充图.例如，如果您的数据点位于{(1.1，3)，(2，4)，(2.9,5)}，则x范围将设置为[1.1:2.9].

Would fill the plot in the x direction based on where the actual data lie. For instance if you had data points at {(1.1, 3), (2, 4), (2.9,5)}, the x range would be set to [1.1:2.9].

这篇关于gnuplot:范围内的最大值和最小值的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！