MagicPlot Manual

Plotting and nonlinear fitting software

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integration [Tue May 11 13:22:26 2010]
Alexander
integration [Thu Jan 14 17:20:17 2021] (current)
Alexander
Line 1: Line 1:
 ====== Integration ===== ====== Integration =====
 +Open Table or Figure or Fit Plot with initial data and select ''Processing -> Integrate'' menu item.
  
-Open Table or Figure or Plot with initial data and use ''Analysis → Integrate'' menu item.+{{:integrate.png?nolink|}}
  
-===== Formula =====+===== Baseline Correction ===== 
 +If your initial data to be integrated contains a baseline (usually constant or linear), you may want to subtract it from data **before** integrating. (A constant baseline will result in linearly growing integral.)  
 + 
 +In such case the algorithm may be the following: 
 +  - Create Fit Plot with your initial table data 
 +  - Add a Fit Curve which simulates the baseline. You may specify a custom equation 
 +  - Specify Fit Interval so that it contains only noise points 
 +  - Fit the data by clicking ''Fit Sum'' button 
 +  - Subtract the baseline fitting curve from data by checking ''Baseline'' checkbox in curves list 
 +  - Use menu ''Processing → Integrate'' to integrate the plotted data without baseline. 
 + 
 +===== Algorithm =====
 To perform integration you should specify two columns: //x// and //y//. Missing values are ignored. To perform integration you should specify two columns: //x// and //y//. Missing values are ignored.
  
 MagicPlot uses [[wp>Trapezoidal_rule|trapezoidal rule]] to compute the integral: MagicPlot uses [[wp>Trapezoidal_rule|trapezoidal rule]] to compute the integral:
  
-<m>I_n = sum{i=1}{n − 1}{(x_{i+1} − x_i) {y_{i+1} + y_i} / 2},~ n=1...N</m>+<m>I_n = 1/2 sum{i=2}{n}{(x_i} − x_{i − 1}) ({y_i + y_{i − 1})},~ n=2...N;~~ I_1=0</m>
  
 +===== See Also =====
 +  * [[processing]]
 +  * [[Differentiation]]
integration.1273569746.txt.gz · Last modified: Sun Nov 8 12:20:32 2015 (external edit)