Error when calculating the distance between two three-dimensional points

Hi,

I have a cell array that contains cells in which there are numerical arrays with 9 columns. In that numerical array the columns 1-3 are x, y, and z coordinates of point A. The columns 4-6 are x, y, and z coordinates of point B. And the columns 7-9 are x, y, and z coordinates of point C.

I wrote this code to measure the distances between point C and A.

for i = 1:numel(pre_xyz)
    right_hand{i} = sqrt((pre_xyz{i}(:,7)-pre_xyz{i}(:,1)).^2 + (pre_xyz{i}(:,8)-pre_xyz{i}(:,2)).^2 + (pre_xyz{i}(:,9)-pre_xyz{i}(:,3)).^2);
end

But I get this error:

Operator '-' is not supported for operands of type 'cell'.

What is the easiest fix for this?

Thanks!

[Walter Roberson]

I have a cell array that contains cells in which there are numerical arrays with 9 columns.

load pre_xyz
pre_xyz{1}(1:5,:)

ans = 5×9 cell array
    {[-0.2839]}    {[1.6748]}    {[-0.2873]}    {[-0.2134]}    {[1.3676]}    {[-0.5863]}    {[-0.0471]}    {[1.3579]}    {[-0.5301]}
    {[-0.2839]}    {[1.6748]}    {[-0.2873]}    {[-0.2124]}    {[1.3671]}    {[-0.5861]}    {[-0.0474]}    {[1.3579]}    {[-0.5299]}
    {[-0.2839]}    {[1.6748]}    {[-0.2873]}    {[-0.2124]}    {[1.3671]}    {[-0.5861]}    {[-0.0474]}    {[1.3579]}    {[-0.5299]}
    {[-0.2838]}    {[1.6748]}    {[-0.2866]}    {[-0.2130]}    {[1.3676]}    {[-0.5846]}    {[-0.0475]}    {[1.3576]}    {[-0.5286]}
    {[-0.2838]}    {[1.6748]}    {[-0.2866]}    {[-0.2130]}    {[1.3676]}    {[-0.5845]}    {[-0.0475]}    {[1.3576]}    {[-0.5286]}

No you do not. You have a cell array that contains cell arrays.

Answer 1

[Walter Roberson]

for i = 1:numel(pre_xyz)
    this_pre = cell2mat(pre_xyz{i});
    right_hand{i} = sqrt((this_pre(:,7)-this_pre(:,1)).^2 + (this_pre(:,8)-this_pre(:,2)).^2 + (this_pre(:,9)-this_pre(:,3)).^2);
end