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How to normalize negative values in a data set/ Matrix

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Amine Ben Ayara
Amine Ben Ayara 2016-12-22
评论： Amine Ben Ayara 2016-12-23
Hello Matlab community, I have a large matrix (14680*751), each row contains data that need to be plotted(i.e., supply curve with $ values from $0to $750 on the Y axis, and carbon values on the X axis). The problem is that in each row of the matrix, there are negative values. I need to find a way to "normalize" that part of the data between the largest negative value and zero (or the first positive value basically). I attached an extract of smaller matrix B(5*20) as an example. Any suggestions are very welcome, Thank you so much, Amine
%%%%%%%Extracted data from the Big Matrix (14680*751)
%%%%%%The matrix B is extracted from the big matrix, and it is B(5*20).
%%%%%%Although some of the elements in each row are negative, they do
%%%%%%start as largely negative then start getting less negativem until
%%%%%%eventually become positive. I am trying to account for that
%%%%%%positive/marginal change or increase, because it will not make sense
%%%%%%to draw supply curves with negative values ( in microecon terms)
B=[-1.47050945378040,-1.33723076144265,-1.19710409742796,-1.05106843381422,-0.900466995312922,-0.746914945492757,-0.592176008533142,-0.438045007240660,-0.286240437664041,-0.138313835492564,0.00441798717200874,0.140914454629432,0.270426543336554,0.392489054463601,0.506895095263594,0.613658893661642,0.712972854741569,0.805163805329556,0.890652051537956,0.969915518856181;-0.841090365686416,-0.686274427020633,-0.556431695216317,-0.449093773011548,-0.361384764288333,-0.290371869645241,-0.233288673385882,-0.187655786921658,-0.151328669223115,-0.122499161299674,-0.0996709425690201,-0.0816227428265286,-0.0673679677609770,-0.0561156700226243,-0.0472353342648724,-0.0402264293996578,-0.0346928170470040,-0.0303216587858231,-0.0268662715145261,-0.0241323310815124;-2.64507912619384,-2.40991384421216,-2.17105653546875,-1.93366471136480,-1.70269068347321,-1.48245802198959,-1.27636167919902,-1.08672279348013,-0.914792168536810,-0.760868562974244,-0.624485460634832,-0.504621811603991,-0.399902903949281,-0.308771004232425,-0.229617388582594,-0.160875900735791,-0.101083038049412,-0.0489115411314220,-0.00318456064689654,0.0371234203291033;-2.95276774937878,-2.83569951619061,-2.71526650996296,-2.58659467339223,-2.44880054835685,-2.30197219410272,-2.14655597853063,-1.98323309778354,-1.81288944691232,-1.63659668475129,-1.45558765005061,-1.27122345915643,-1.08495324528020,-0.898268831972023,-0.712657273810505,-0.529554417479638,-0.350302480998157,-0.176114165152570,-0.00804508666750537,0.153024525436801;-2.05772480055009,-1.78667734692683,-1.52520993070707,-1.28101965824359,-1.05961385350071,-0.864075447044489,-0.695268465690161,-0.552316595400815,-0.433173665056002,-0.335151455327047,-0.255334769254064,-0.190866870884295,-0.139120071476573,-0.0977789501638324,-0.0648644005650677,-0.0387217871127744,-0.0179901264477179,-0.00156345495988809,0.0114488783805824,0.0217593252262164]
Y_dollars=(0:19);
%%%%%%For example plot if I plot row 1 from B
plot(B(1,:),Y_dollars)
%%%The resulting graph shows a curve increasing at an increasing rate from
%%%-1.5 to almost 2.8.... Part of the datat is between -1.5 and 0 needs to
%%%be normalized (from what I understand). ..
%%%%The challenge is that I have 14680 of these rows to derive supply
%%%%curves for, and in each row the data vary in the inetevall from
%%%%negative to zero (or to the very first positive value)
%%%The Question: can this be done using a matlab command to normalize the
%%%part of each supply curve/ data in each row to when I draw the curves
%%%they all start from zero (non-negative vlaues basically)?
  2 个评论
Walter Roberson
Walter Roberson 2016-12-22
You have not indicated what they need to be normalized to .
Amine Ben Ayara
Amine Ben Ayara 2016-12-22
编辑：Walter Roberson 2016-12-22
Hello Walter,
maybe I am using the wrong word. But I do need to basically adjust the negative part in each row of the entire matrix so when supply curves are drawn they start from zero ( for example in row 1 from the example matrix B; the following elements are negative, yet they get less negative until they reach zero
(-1.47050945378040 -1.33723076144265 -1.19710409742796 -1.05106843381422 -0.900466995312922 -0.746914945492757 -0.592176008533142 -0.438045007240660 -0.286240437664041 -0.138313835492564 0.00441798717200874)
so there is am increase, but when I plot the data in that 1st row as it is, the line starts with negative values, hence misleading

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采纳的回答

Image Analyst
Image Analyst 2016-12-22
Another way:
m = magic(11) % Sample data
rowMins = min(m, [], 2)
mMins = repmat(rowMins, [1, size(m, 2)])
normalizedM = m - mMins

更多回答（1 个）

Walter Roberson
Walter Roberson 2016-12-22
If the normalization is to be done over the whole matrix:
normalized_B = B - min(0, min(B(:)));
If the normalization is to be done per-row:
min_B = max(0, min(B,[], 2));
then
normalized_B = B - min_B; %requires R2016b or later
or
normalized_B = bsxfun(@minus, B, min_B); %R2007a or later
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