How can I fix error matrix dimensions must agree?

1 次查看（过去 30 天）
Gimil
Gimil 2014-4-19
评论： Image Analyst 2014-4-20
This is suppose to produce any shape on a graph and shift it 4 units to the right and 2 units down with one input. I am getting told that there is error in matrix dimensions.
function [Row1,Row2] = problem3(nSides)
r = 1;
theta = pi./nSides .* (1:2:2*nSides-1);
Row1 = r .* cos(theta);
Row2 = r .* sin(theta);
fill(Row1+4,Row2-2,'k');
axis square; grid on;
end
  10 个评论
显示 8更早的评论
Image Analyst
Image Analyst 2014-4-19
编辑：Image Analyst 2014-4-19
My answer below works just fine. Try this:
[Row1,Row2] = problem3(5);
It produces two plots. The original one, and the shifted one. Isn't that what you want?
Geoff Hayes
Geoff Hayes 2014-4-19
Re-reading the problem definition a second time indicates that the input is not a scalar but a 2xN matrix of N coordinates. And that it is the shape defined by these coordinates that is shifted 4 units down and 2 to the right. The output of this function is another 2xN matrix with the shifted coordinates.
The body of the provided code seems more complex than what the solution to the problem requires.

请先登录，再进行评论。

请先登录，再回答此问题。

回答（1 个）

Image Analyst
Image Analyst 2014-4-19
编辑：Image Analyst 2014-4-19
It's trivial. Just repeat the code after adding 4 and subtracting 2:
function [Row1,Row2] = problem3(nSides)
% First the original, unshifted plot.
subplot(1, 2, 1);
r = 1;
theta = pi./nSides .* (1:2:2*nSides-1);
Row1 = r .* cos(theta);
Row2 = r .* sin(theta);
fill(Row1+4, Row2-2, 'k');
grid on;
xlim([0 9]);
ylim([-5, 0]);
axis equal;
% Now shift 4 units to the right and 2 units down.
subplot(1, 2, 2);
Row1 = Row1 + 4;
Row2 = Row2 - 2;
fill(Row1+4, Row2-2, 'k');
grid on;
xlim([0 9]);
ylim([-5, 0]);
axis equal;
Get rid of the subplot() calls if you want it all on one axes. Put a "hold on" in there if you don't want the second plot to blow away the first one.
  1 个评论
Image Analyst
Image Analyst 2014-4-20
Then nSides is a bad name for that input argument. When it's called nSides, you'd think it was the number of sides, and in fact your code does draw an n-sided polygon. So what should the inside of the function be? Should it just plot the coordinates:
x = nSides(:,1);
y = nSides(:, 2);
plot(x, y, 'bo-', 'LineWidth', 2, 'MarkerSize', 15);
hold on;
plot(x+4, y-2, 'bo-', 'LineWidth', 2, 'MarkerSize', 15);

请先登录，再进行评论。

类别

在 Help Center 和 File Exchange 中查找有关 Graphics Performance 的更多信息

标签

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by