OriginLab® Introduction to Fit Multiple Datasets Video Lecture - Origin

in this tutorial I will show you how to
perform an independent fit of multiple
data sets you'll also learn how to apply
the parameter values of one data set to
the other data sets we begin with a
stacked layer graph and we have a
fitting function a user-defined function
that actually ships with the product is
located in samples curve fitting we're
going to take that previously defined
function drop it on to origin which will
install it so the function is available
to us from within the software we
specify the category to make it
available we'll leave it as user-defined
click OK
the file gets copied over to the user
files folder where all your other
user-defined fitting functions would be
if I open up the nonlinear curve fit
dialog analysis fitting nonlinear curve
fit open the dialog I then want to
change my category to user-defined so
that I can select my new function from
the function drop-down after selecting
your function the next step is to go to
data selection the input data will be
pre-populated from the active data set
in the active layer we're going to now
add all plots in the active page so it
will add to range to range input so we
should arrange one two and three one for
each of our data plots and each of the
layers going to the parameters tab we
will look at there'll be three sets of
parameters the default initial values
for the first set is just one we'll
leave these for now and we're going to
click on one iteration these are to rip
the iteration and fit until converge
buttons work for the highlighted data
set above okay there's an index drop
down so it's for the first data plot
that we're fitting our first range we're
going to go ahead and fit with those
default parameter values and as we see
from the fit curve displayed on the
graph it's not a very good fit we're
going to need to find out find some
better initial parameter values so we
can go back to the parameters tab and we
can enter in values so let's go ahead
and change that one parameter there B
let's enter in negative one as a new
initial value after doing that we can
update the fit curve by simply clicking
one iteration
as we do that you can watch the thick
curve on the graph update and check if
the fit improves
clicking again the fit will continue to
improve and now we can fit until
converged look at the fit curve on the
graph the fit of that first data set
looks pretty good
we're now going to take those set of
parameter values and we right-click to
pop up the context menu and we're going
to apply that set of values to all the
other data sets that we're fitting the
other two data sets to initialize the
parameter values watch those those
values update in that parameters table
we can select the second data set that
will highlight above in the table we can
click fit until converge to fit the
second data set as you do that watch in
your lair in your graph there and update
you'll see the the fit curves drawn
if we click done the dialogue will be
closed with only the first two datasets
fit you can see that our decay 3 doesn't
look so good we need to update the we
need to do more iterations so what we're
going to do is click on fit to fit all
the data sets so it'll fit until
converges would give us some error if
they don't fit so doing that will fit
and then close the dialog the parameter
table is output here so we can maximize
this and you can see the fit parameters
that were found as for decay 1 2 & 3 as
part of the fitting we're going to go to
project Explorer and open up the
workbook where we have our report sheet
to created with the fit results there's
a parameters table the statistics table
we can scroll down here we have the
fitted curve we also have the residual
plots this concludes this tutorial thank
you for watching