Area under curve using trapz
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Hello,
I am trying to calculate the area under the curve and partial area under the curve for a scalogram created from a wavelet. The scalograms x axis is logarithmic and the y axis is linear. The values I get when I attempt to run it do not make sense.
2 个评论
Andy
2019-7-30
Your question does not give enough information; What is the data you are using? What code are you using? What answers are you getting?
回答（1 个）
Priyanshu Mishra
2019-8-2
I am assuming that you have changed your X axis values in logarithmic scale and stored it in the new variable.
Now, use the function trapz to calculate the complete area under the curve where, variable ‘X’ should be logarithmic values.
For partial area under the curve, you can use the following sample code:
% let us assume that you want to calculate area in the range [5:15]
Index_begin= 5 ;
Index_end= 15;
X_new= x(Index_begin:Index_end); % x is contains all the values in X axis
Y_new= y(Index_begin:Index_end); % y contains all the values in Y axis
Partial_area = trapz(X_new,Y_new);
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2019-7-30
2019-8-2
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