shift array to flat
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hello,
i have a 142 element array that generates a curve (attached). when a line is drawn from end to end the line is at a certain (unknown) slope. how could i adjust the values in the array so that when plotted and a line drawn from end to end of the curve, the slope is 0?
picture and array is attached.
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Cedric
2017-10-7
编辑:Cedric
2017-10-7
plot( unnamed, 'b' ) ;
hold on ; grid on ;
x = (1 : length(unnamed)).' - 1 ;
slope = (unnamed(end) - unnamed(1)) / (length(unnamed) - 1) ;
y = unnamed - (unnamed(1) + x * slope) ;
plot( y, 'g' ) ;
but we often need something else :
plot( detrend( unnamed ), 'r' ) ;
with
>> mean( detrend( unnamed ))
ans =
-3.9612e-18
>> mean( y )
ans =
-0.0011
2 个评论
Cedric
2017-10-7
编辑:Cedric
2017-10-7
doc detrend : removes linear trend.
What I understood from your question was that you wanted the green line on my plot, which is the curve shifted up based on the value defined by the black line. If it is correct, this is what I compute/define as y.
Thinking a bit more about it, you may want
y = unnamed - x * slope ;
if you want the first value to match.
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