My interpolation works for one set, but does not work for the other

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Ismail Qeshta
Ismail Qeshta 2017-11-12
评论： Ismail Qeshta 2017-11-12
Hi,
I am using the following code for interpolation from data in files. The problem is that the code runs very nicely in the first set, X1, Y1, while it shows that the X and V values don't have the same length in the second set: X2, Y2. I can't figure out the problem. Both codes present the same type of results and have same column length. The files of both sets are attached herewith.
clear; clc;
y=load ('Y1.txt');
x=load ('X1.txt');
plot(x(:,2),-sum(y(:,2:11),2))
y1=-sum(y(:,2:11),2);
x1=x(:,2);
y3=unique(y1);
x3=unique(x1);
y2 = [1308.9, 2514.9, 4797.9]*1000;
x2 = interp1(y3, x3, y2, 'linear');
figure(1)
plot(x1, y1, '-g')
hold on
plot(x2, y2, 'bp')
hold off
grid
legend('Data', 'Interpolated Points', 'Location', 'NW')
  1 个评论
Ismail Qeshta
Ismail Qeshta 2017-11-12
编辑：Ismail Qeshta 2017-11-12
Error message is the following:
Error using interp1>reshapeAndSortXandV (line 423)
X and V must be of the same length.
Error in interp1 (line 92)
[X,V,orig_size_v] = reshapeAndSortXandV(varargin{1},varargin{2});
Error in Interpolate (line 15)
x2 = interp1(y3, x3, y2, 'linear');

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采纳的回答

Jan
Jan 2017-11-12
编辑：Jan 2017-11-12
The message is clear:
X and V must be of the same length.
Set a breakpoint in the failing line and check the dimensions:
size(y3)
size(x3)
Or:
y = load('Y2.txt');
x = load('X2.txt');
y1 = -sum(y(:,2:11),2);
x1 = x(:,2);
y3 = unique(y1);
x3 = unique(x1);
size(y3)
size(x3)
ans =
5504 1
ans =
5501 1
Then an interpolation is not possible. A solution might be:
[x3, ix] = unique(x1);
y3 = y1(ix);
  2 个评论
Ismail Qeshta
Ismail Qeshta 2017-11-12
Hi Jan,
Yes. You are right. I have just checked it. Do you have any idea on how to solve this issue? Thanks.
a= size(y3)
b= size(x3)
a =
1220 1
b =
1215 1

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