Question

OSX v10.10.5和Gnuplot v5.0

我有一个包含三列数字的数据文件，我读取了存储在里面的值来进行一些计算。但这很耗时！

这是我到目前为止所做的：

#user defined function to read data in a file
#see stackoverflow: "Reading dataset value into a gnuplot variable (start of X series)"
at(file, row, col) = system( sprintf("awk -v row=%d -v col=%d 'NR == row {print $col}' %s", row, col, file) )
file="myFile"

do for [k=1:10] { #we read line by line and we want the ratio between column 2/1 and 3/1
f(k) = at(file,k,2)/at(file,k,1)
g(k) = at(file,k,3)/at(file,k,1)

# example of calculation: least square to find the best "i"
do for [i=1:10] {
    f1(i) = (a*i**2 + b*i + c) #function for the least square. a,b,c: floats
    g1(i) = (d*i**2 + e*i + f) #d,e,f: floats
    h(i) = sqrt( (f1(i)-f(k))**2 + (g1(i)-g(k))**2 )
    if (h(i)<hMin) {
        hMin=h(i)
                   }
    else {}
            } #end loop i
print i," ",hMin
} #end loop k

它有效，但正如我所说，它需要时间（每k约2分钟）。当我不进行任何计算并仅询问打印f（k），g（k）时，它是＆lt;＆lt; 1秒。我怀疑这种划分可能导致数字过多而计算效率低下。我使用round2函数来保持n = 4：

#see stackoverflow: How to use floor function in gnuplot
round(x) = x - floor(x) < 0.5 ? floor(x) : ceil(x)
round2(x, n) = round(x*10**n)*10.0**(-n)
f(k) = round2((at(file,k,2)/at(file,k,1)),4)
g(k) = round2((at(file,k,3)/at(file,k,1)),4)

但它没有改变所需的时间。关于发生了什么的任何想法？

Answer 1

您没有发布完整代码（缺少a，b，...，f的定义）。但是在您发布的代码部分内，我认为您可以避免经常调用f(k)。您可以使用简单变量g(k)和fk替换函数gk和#user defined function to read data in a file #see stackoverflow: "Reading dataset value into a gnuplot variable (start of X series)" at(file, row, col) = system( sprintf("awk -v row=%d -v col=%d 'NR == row {print $col}' %s", row, col, file) ) file="myFile" do for [k=1:10] { #we read line by line and we want the ratio between column 2/1 and 3/1 at1 = at(file,k,1) fk = at(file,k,2)/at1 gk = at(file,k,3)/at1 # example of calculation: least square to find the best "i" do for [i=1:10] { f1i = (a*i**2 + b*i + c) #function for the least square. a,b,c: floats g1i = (d*i**2 + e*i + f) #d,e,f: floats hi = sqrt( (f1i-fk)**2 + (g1i-gk)**2 ) if (hi<hMin) { hMin=hi } else { } } #end loop i print i," ",hMin } #end loop k，因为事实上它们在每次k迭代中都是常量。似乎没有必要在每次迭代中重新计算它们。

WEB-INF/{\*.jar}!/META-INF/resources/

但是在丢失的代码中可能会有更多有趣的细节抑制这个解决方案。

gnuplot使用从文件读取的数据来固定进程

1 个答案: