MATLAB: How to interpolate column

interpolate

I have a matrix with 3 rows want to increase it to 5

how sould i do it ?

A=[1,1.2,1.4,1.6,1.8;1.3,1.6,1.7,2,2.2;1.8,2,2.5,2.6,2.7]

i want to keep the min amd max value as it is and the values in between should be interpolated

Best Answer

What about:

A = [1,1.2,1.4,1.6,1.8; ...
     1.3,1.6,1.7,2,2.2; ...
     1.8,2,2.5,2.6,2.7];
n = 7;
B = interp1(1:size(A, 2), A.', linspace(1, size(A, 2), n))

Related Solutions

MATLAB: How to fit a series of datapoints using 3 piecewise linear fit lines

Use this FEX

load data.mat % attached above
ydata(end) = []; % your xdata/ydata do not match in length ! 
slope0 = struct('p', 1, 'x', [min(xdata) max(xdata)], 'v', [0 0]);
% Download BSFK function here
% https://www.mathworks.com/matlabcentral/fileexchange/25872-free-knot-spline-approximation
pp = BSFK(xdata,ydata, 2, 3, [], struct('KnotRemoval', 'none', 'pntcon', slope0)); 
% Check
figure
xi = linspace(min(xdata),max(xdata));
yi = ppval(pp,xi)
plot(xdata,ydata,'b',xi,yi,'r');
for xb=pp.breaks
    xline(xb);
end
grid on

MATLAB: How to insert a new column to a matrix after its every two column

A more generic version of Stephen's method 1:

skipcolumns = 2;
bcols = (1:size(b, 2)) * (skipcolumns+1);
assert(size(b, 2) * skipcolumns == size(A, 2), 'number of columns in A and b don''t match skipcolumns');
acols = setdiff(1:size(b, 2)+size(A, 2), bcols);
new1(:, bcols) = b;
new1(:, acols) = A;

a more generic version of method 2:

skipcolumns = 2;
assert(size(b, 2) * skipcolumns == size(A, 2), 'number of columns in A and b don''t match skipcolumns');
new2 = reshape([reshape(A, size(A, 1)*skipcolumns, []); b], size(A, 1), [])

Best Answer

Related Solutions

MATLAB: How to fit a series of datapoints using 3 piecewise linear fit lines

MATLAB: How to insert a new column to a matrix after its every two column

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