Use linspace without scalar input?

I want to use linspace that goes from two non-scalar terms. Is there a way to use linspace with specified number of points, n, for decimal values for inputs? Example code is below for what I am looking for.

x = 0.01;
y = [1.01, 3.01];
n = 10;
dxy = linspace(x, y, n);

[the cyclist]

Rather than telling us an input syntax that clearly doesn't work, it might be better to tell us what output you are hoping to get.

It seems like you are trying to over-specify what you want to get.

[KSSV]

n cannot be a decimal.....it should be an integer.

[Andrew Poissant]

My apologies. n will be an integer since it is the number of points. I want to use decimal values for x and y. So part of the output I am looking for would be dxy = [0.01 0.11 0.21 ... 1.01; 0.01 0.11 0.21 ... 3.01]. Hope this makes things clearer.

Answer 1

[Guillaume]

x = 0.01;
y = [1.01, 3.01];  %would be better as a column vector as you wouldn't to tranpose it in the arrayfun
n = 10;
dxy = cell2mat(arrayfun(@(e) linspace(x, e, n), y', 'UniformOutput', false))

Or using a loop:

x = 0.01;
y = [1.01, 3.01];  %would be better as a column vector as you wouldn't to tranpose it in the arrayfun
n = 10;
dxy = zeros(numel(y), n);
for row = 1:numel(y)
   dxy(row, :) = linspace(x, y(row), n);
end

or using Jan's idea but with R2016b or later syntax:

x = 0.01;
y = [1.01, 3.01];  %would be better as a column vector as you wouldn't the transpose in the calculation of dxy
n = 10;  

dxy = (0:n-1) .* (y'-x)/n + x

[Andrew Poissant]

Thank you! Your answer was very helpful

[Ali Talha Atici]

Thank you, Guillaume,

I have a little update to the last script to match the results.

x = 0.01;
y = [1.01, 3.01];  %would be better as a column vector as you wouldn't the transpose in the calculation of dxy
n = 10;  
dxy = (0:n-1) .* (y'-x)/(n-1) + x

Answer 2

[Jan]

x   = 0.01;
y   = [1.01, 3.01];
n   = 10;
dxy = [linspace(x, y(1), n); ...
       linspace(x, y(2), n)];

Or:

Step = repmat((y(:) - x(:)) / (n - 1), 1, n);
Step(:, 1) = x(:);
dxy  = cumsum(Step);

[Andrew Poissant]

How would I generalize the first option if I have many values in the y vector? I tried the following:

for i = 1:length(y)
    dxy(i) = linspace(x, y(i), n);
end

but got the error "Subscripted assignment dimension mismatch."

Answer 3

[Stephen23]

An efficient general solution for any size y using linspace and bsxfun:

>> x = 0.01;
>> y = [1.01, 3.01];
>> n = 10;
>> bsxfun(@plus,x*linspace(1,0,n),bsxfun(@times,y(:),linspace(0,1,n)))
ans =
   0.010000   0.121111   0.232222   0.343333   0.454444   0.565556   0.676667   0.787778   0.898889   1.010000
   0.010000   0.343333   0.676667   1.010000   1.343333   1.676667   2.010000   2.343333   2.676667   3.010000

MATLAB versions with implicit expansion could probably do this (untested):

x.*linspace(1,0,n) + y(:).*linspace(0,1,n)

[Andrew Poissant]

Thank you!