How to obtain point data from a fitting curve?
1
I plotted curves by fitting some existing points using gnuplot.
code as followings:
f1(x)=a1/(x**b1)+c1
fit f1(x) "41a091_input.txt" u 1:2 via a1,b1,c1
plot f1(x) with line lt 1 lw 4 lc rgb "blue" notitle,
'41a091_input.txt' using 1:2:3 with yerrorbars lw 2.2 lc rgb "blue" title "∑41a(091)"
Data as followings:
21.8124 1.11693 0.00545168
30.8669 1.07328 0.00485237
44.6701 1.04708 0.00411839
53.6699 1.03787 0.00301346
75.9751 1.02555 0.00304312
My question is:
How to get data from any point on this curve?
Like when x=50?
gnuplot curve-fitting
edited Nov 29 '18 at 18:59
Christoph
39.1k847122
asked Nov 29 '18 at 0:27
JunChaiJunChai
83
add a comment |
1
I plotted curves by fitting some existing points using gnuplot.
code as followings:
f1(x)=a1/(x**b1)+c1
fit f1(x) "41a091_input.txt" u 1:2 via a1,b1,c1
plot f1(x) with line lt 1 lw 4 lc rgb "blue" notitle,
'41a091_input.txt' using 1:2:3 with yerrorbars lw 2.2 lc rgb "blue" title "∑41a(091)"
Data as followings:
21.8124 1.11693 0.00545168
30.8669 1.07328 0.00485237
44.6701 1.04708 0.00411839
53.6699 1.03787 0.00301346
75.9751 1.02555 0.00304312
My question is:
How to get data from any point on this curve?
Like when x=50?
gnuplot curve-fitting
edited Nov 29 '18 at 18:59
Christoph
39.1k847122
asked Nov 29 '18 at 0:27
JunChaiJunChai
83
add a comment |
1
1
1
I plotted curves by fitting some existing points using gnuplot.
code as followings:
f1(x)=a1/(x**b1)+c1
fit f1(x) "41a091_input.txt" u 1:2 via a1,b1,c1
plot f1(x) with line lt 1 lw 4 lc rgb "blue" notitle,
'41a091_input.txt' using 1:2:3 with yerrorbars lw 2.2 lc rgb "blue" title "∑41a(091)"
Data as followings:
21.8124 1.11693 0.00545168
30.8669 1.07328 0.00485237
44.6701 1.04708 0.00411839
53.6699 1.03787 0.00301346
75.9751 1.02555 0.00304312
My question is:
How to get data from any point on this curve?
Like when x=50?
gnuplot curve-fitting
edited Nov 29 '18 at 18:59
Christoph
39.1k847122
asked Nov 29 '18 at 0:27
JunChaiJunChai
83
I plotted curves by fitting some existing points using gnuplot.
code as followings:
f1(x)=a1/(x**b1)+c1
fit f1(x) "41a091_input.txt" u 1:2 via a1,b1,c1
plot f1(x) with line lt 1 lw 4 lc rgb "blue" notitle,
'41a091_input.txt' using 1:2:3 with yerrorbars lw 2.2 lc rgb "blue" title "∑41a(091)"
Data as followings:
21.8124 1.11693 0.00545168
30.8669 1.07328 0.00485237
44.6701 1.04708 0.00411839
53.6699 1.03787 0.00301346
75.9751 1.02555 0.00304312
My question is:
How to get data from any point on this curve?
Like when x=50?
gnuplot curve-fitting
gnuplot curve-fitting
edited Nov 29 '18 at 18:59
Christoph
39.1k847122
asked Nov 29 '18 at 0:27
JunChaiJunChai
83
edited Nov 29 '18 at 18:59
Christoph
39.1k847122
asked Nov 29 '18 at 0:27
JunChaiJunChai
83
edited Nov 29 '18 at 18:59
Christoph
39.1k847122
edited Nov 29 '18 at 18:59
Christoph
39.1k847122
edited Nov 29 '18 at 18:59
Christoph
39.1k847122
39.1k847122
asked Nov 29 '18 at 0:27
JunChaiJunChai
83
asked Nov 29 '18 at 0:27
JunChaiJunChai
83
asked Nov 29 '18 at 0:27
JunChaiJunChai
83
83
add a comment |
add a comment |
1 Answer
1
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oldest
votes
1
well, you have your fitting function f1(x) and the parameters a1,b1,c1 have been fitted. So, in order to get the value at x=50, simply type print f1(50).
Or if you want to plot it:
### start code
reset session
$Data <<EOD
21.8124 1.11693 0.00545168
30.8669 1.07328 0.00485237
44.6701 1.04708 0.00411839
53.6699 1.03787 0.00301346
75.9751 1.02555 0.00304312
EOD
f1(x)=a1/(x**b1)+c1
fit f1(x) $Data u 1:2 via a1,b1,c1
print sprintf("a1: %g, b1: %g, c1: %g", a1,b1,c1)
XValue = 50
set label 1 at XValue,f1(XValue)+0.01 sprintf("f1(%g): %g",XValue,f1(XValue))
set arrow 1 from XValue,graph 0 to XValue,graph 1 nohead ls 0
plot f1(x) with line lt 1 lw 4 lc rgb "blue" notitle,
$Data using 1:2:3 with yerrorbars lw 2.2 lc rgb "blue" title "∑41a(091)",
[XValue:XValue] f1(XValue) w p lt 6 lc rgb "red" ps 2
### end of code
which results in something like:
answered Nov 29 '18 at 5:48
theozhtheozh
1,578312
OMG you saved my life! That works! However i still do not understand some details, like what does [XValue:XValue] using for?
– JunChai
Nov 29 '18 at 15:40
And what if i want to add a vertical dashed line through this point?
– JunChai
Nov 29 '18 at 15:55
just remove the[XValue:XValue]and see what will happen. This limits the range to one datapoint. Vertical dashed line: for example withset arrow 1 from XValue, graph 0 to XValue, graph 1 nohead ls 0Maybe there are better ways to achieve both things.
– theozh
Nov 29 '18 at 18:48
Probably a better way to plot a single pointplot '+' using (XValue):(f1(XValue)) w p lt 6 lc rgb "red" ps 2
– theozh
Nov 29 '18 at 21:30
add a comment |
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1 Answer
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active
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1 Answer
1
active
oldest
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active
oldest
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oldest
votes
1
well, you have your fitting function f1(x) and the parameters a1,b1,c1 have been fitted. So, in order to get the value at x=50, simply type print f1(50).
Or if you want to plot it:
### start code
reset session
$Data <<EOD
21.8124 1.11693 0.00545168
30.8669 1.07328 0.00485237
44.6701 1.04708 0.00411839
53.6699 1.03787 0.00301346
75.9751 1.02555 0.00304312
EOD
f1(x)=a1/(x**b1)+c1
fit f1(x) $Data u 1:2 via a1,b1,c1
print sprintf("a1: %g, b1: %g, c1: %g", a1,b1,c1)
XValue = 50
set label 1 at XValue,f1(XValue)+0.01 sprintf("f1(%g): %g",XValue,f1(XValue))
set arrow 1 from XValue,graph 0 to XValue,graph 1 nohead ls 0
plot f1(x) with line lt 1 lw 4 lc rgb "blue" notitle,
$Data using 1:2:3 with yerrorbars lw 2.2 lc rgb "blue" title "∑41a(091)",
[XValue:XValue] f1(XValue) w p lt 6 lc rgb "red" ps 2
### end of code
which results in something like:
answered Nov 29 '18 at 5:48
theozhtheozh
1,578312
OMG you saved my life! That works! However i still do not understand some details, like what does [XValue:XValue] using for?
– JunChai
Nov 29 '18 at 15:40
And what if i want to add a vertical dashed line through this point?
– JunChai
Nov 29 '18 at 15:55
just remove the[XValue:XValue]and see what will happen. This limits the range to one datapoint. Vertical dashed line: for example withset arrow 1 from XValue, graph 0 to XValue, graph 1 nohead ls 0Maybe there are better ways to achieve both things.
– theozh
Nov 29 '18 at 18:48
Probably a better way to plot a single pointplot '+' using (XValue):(f1(XValue)) w p lt 6 lc rgb "red" ps 2
– theozh
Nov 29 '18 at 21:30
add a comment |
1
well, you have your fitting function f1(x) and the parameters a1,b1,c1 have been fitted. So, in order to get the value at x=50, simply type print f1(50).
Or if you want to plot it:
### start code
reset session
$Data <<EOD
21.8124 1.11693 0.00545168
30.8669 1.07328 0.00485237
44.6701 1.04708 0.00411839
53.6699 1.03787 0.00301346
75.9751 1.02555 0.00304312
EOD
f1(x)=a1/(x**b1)+c1
fit f1(x) $Data u 1:2 via a1,b1,c1
print sprintf("a1: %g, b1: %g, c1: %g", a1,b1,c1)
XValue = 50
set label 1 at XValue,f1(XValue)+0.01 sprintf("f1(%g): %g",XValue,f1(XValue))
set arrow 1 from XValue,graph 0 to XValue,graph 1 nohead ls 0
plot f1(x) with line lt 1 lw 4 lc rgb "blue" notitle,
$Data using 1:2:3 with yerrorbars lw 2.2 lc rgb "blue" title "∑41a(091)",
[XValue:XValue] f1(XValue) w p lt 6 lc rgb "red" ps 2
### end of code
which results in something like:
answered Nov 29 '18 at 5:48
theozhtheozh
1,578312
OMG you saved my life! That works! However i still do not understand some details, like what does [XValue:XValue] using for?
– JunChai
Nov 29 '18 at 15:40
And what if i want to add a vertical dashed line through this point?
– JunChai
Nov 29 '18 at 15:55
just remove the[XValue:XValue]and see what will happen. This limits the range to one datapoint. Vertical dashed line: for example withset arrow 1 from XValue, graph 0 to XValue, graph 1 nohead ls 0Maybe there are better ways to achieve both things.
– theozh
Nov 29 '18 at 18:48
Probably a better way to plot a single pointplot '+' using (XValue):(f1(XValue)) w p lt 6 lc rgb "red" ps 2
– theozh
Nov 29 '18 at 21:30
add a comment |
1
1
1
well, you have your fitting function f1(x) and the parameters a1,b1,c1 have been fitted. So, in order to get the value at x=50, simply type print f1(50).
Or if you want to plot it:
### start code
reset session
$Data <<EOD
21.8124 1.11693 0.00545168
30.8669 1.07328 0.00485237
44.6701 1.04708 0.00411839
53.6699 1.03787 0.00301346
75.9751 1.02555 0.00304312
EOD
f1(x)=a1/(x**b1)+c1
fit f1(x) $Data u 1:2 via a1,b1,c1
print sprintf("a1: %g, b1: %g, c1: %g", a1,b1,c1)
XValue = 50
set label 1 at XValue,f1(XValue)+0.01 sprintf("f1(%g): %g",XValue,f1(XValue))
set arrow 1 from XValue,graph 0 to XValue,graph 1 nohead ls 0
plot f1(x) with line lt 1 lw 4 lc rgb "blue" notitle,
$Data using 1:2:3 with yerrorbars lw 2.2 lc rgb "blue" title "∑41a(091)",
[XValue:XValue] f1(XValue) w p lt 6 lc rgb "red" ps 2
### end of code
which results in something like:
answered Nov 29 '18 at 5:48
theozhtheozh
1,578312
well, you have your fitting function f1(x) and the parameters a1,b1,c1 have been fitted. So, in order to get the value at x=50, simply type print f1(50).
Or if you want to plot it:
### start code
reset session
$Data <<EOD
21.8124 1.11693 0.00545168
30.8669 1.07328 0.00485237
44.6701 1.04708 0.00411839
53.6699 1.03787 0.00301346
75.9751 1.02555 0.00304312
EOD
f1(x)=a1/(x**b1)+c1
fit f1(x) $Data u 1:2 via a1,b1,c1
print sprintf("a1: %g, b1: %g, c1: %g", a1,b1,c1)
XValue = 50
set label 1 at XValue,f1(XValue)+0.01 sprintf("f1(%g): %g",XValue,f1(XValue))
set arrow 1 from XValue,graph 0 to XValue,graph 1 nohead ls 0
plot f1(x) with line lt 1 lw 4 lc rgb "blue" notitle,
$Data using 1:2:3 with yerrorbars lw 2.2 lc rgb "blue" title "∑41a(091)",
[XValue:XValue] f1(XValue) w p lt 6 lc rgb "red" ps 2
### end of code
which results in something like:
answered Nov 29 '18 at 5:48
theozhtheozh
1,578312
edited Nov 29 '18 at 18:50
answered Nov 29 '18 at 5:48
theozhtheozh
1,578312
answered Nov 29 '18 at 5:48
theozhtheozh
1,578312
answered Nov 29 '18 at 5:48
theozhtheozh
1,578312
1,578312
OMG you saved my life! That works! However i still do not understand some details, like what does [XValue:XValue] using for?
– JunChai
Nov 29 '18 at 15:40
And what if i want to add a vertical dashed line through this point?
– JunChai
Nov 29 '18 at 15:55
just remove the[XValue:XValue]and see what will happen. This limits the range to one datapoint. Vertical dashed line: for example withset arrow 1 from XValue, graph 0 to XValue, graph 1 nohead ls 0Maybe there are better ways to achieve both things.
– theozh
Nov 29 '18 at 18:48
Probably a better way to plot a single pointplot '+' using (XValue):(f1(XValue)) w p lt 6 lc rgb "red" ps 2
– theozh
Nov 29 '18 at 21:30
add a comment |
OMG you saved my life! That works! However i still do not understand some details, like what does [XValue:XValue] using for?
– JunChai
Nov 29 '18 at 15:40
And what if i want to add a vertical dashed line through this point?
– JunChai
Nov 29 '18 at 15:55
just remove the[XValue:XValue]and see what will happen. This limits the range to one datapoint. Vertical dashed line: for example withset arrow 1 from XValue, graph 0 to XValue, graph 1 nohead ls 0Maybe there are better ways to achieve both things.
– theozh
Nov 29 '18 at 18:48
Probably a better way to plot a single pointplot '+' using (XValue):(f1(XValue)) w p lt 6 lc rgb "red" ps 2
– theozh
Nov 29 '18 at 21:30
OMG you saved my life! That works! However i still do not understand some details, like what does [XValue:XValue] using for?
– JunChai
Nov 29 '18 at 15:40
OMG you saved my life! That works! However i still do not understand some details, like what does [XValue:XValue] using for?
– JunChai
Nov 29 '18 at 15:40
And what if i want to add a vertical dashed line through this point?
– JunChai
Nov 29 '18 at 15:55
And what if i want to add a vertical dashed line through this point?
– JunChai
Nov 29 '18 at 15:55
just remove the
[XValue:XValue] and see what will happen. This limits the range to one datapoint. Vertical dashed line: for example with set arrow 1 from XValue, graph 0 to XValue, graph 1 nohead ls 0 Maybe there are better ways to achieve both things.– theozh
Nov 29 '18 at 18:48
just remove the
[XValue:XValue] and see what will happen. This limits the range to one datapoint. Vertical dashed line: for example with set arrow 1 from XValue, graph 0 to XValue, graph 1 nohead ls 0 Maybe there are better ways to achieve both things.– theozh
Nov 29 '18 at 18:48
Probably a better way to plot a single point
plot '+' using (XValue):(f1(XValue)) w p lt 6 lc rgb "red" ps 2– theozh
Nov 29 '18 at 21:30
Probably a better way to plot a single point
plot '+' using (XValue):(f1(XValue)) w p lt 6 lc rgb "red" ps 2– theozh
Nov 29 '18 at 21:30
add a comment |
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