Problem 44950. Calculate Inner Product

Created by Pooja Lalan

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Given two input matrices, <tt>x</tt> and <tt>y</tt>, check if their inner dimensions match.<ul><li>If they match, create an output variable <tt>z</tt> which contains the product of <tt>x</tt> and <tt>y</tt></li><li>Otherwise, <tt>z</tt> should contain a custom string message</li></ul>Example:<pre class="language-matlab">x = [1 2;3 4]
y = [5;6]
</pre><tt>z = [17;39]</tt><pre class="language-matlab">x = [1 2 3;4 5 6]
y = [2 5;3 6]
</pre><tt>z = "Have you checked the inner dimensions?"</tt>OR<tt>z = "The inner dimensions are 3 and 2. Matrix multiplication is not possible"</tt>-------------------------------------------------------------------------------------------------------------------------------------------------------------NOTE - An example of combining numbers and strings together is shown below:<pre class="language-matlab">x = "The sum of " + 4 + " and " + 3 + " equals " + 7
</pre><pre class="language-matlab">x = 
</pre><pre> "The sum of 4 and 3 equals 7"</pre>

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Last Solution submitted on Jun 01, 2023

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Rohiit Priyadarshan Muralidharan on 30 Mar 2020

I solved this question with an if condition and the size of my solution was 39. I found the size of the leading solution to be 14. This is the leading solution: function ans = in_prod(x,y)
"no";
try
x*y;
end
How is this even correct? I tried to paste the same solution instead of mine and the assertion failed. z is not mentioned anywhere in this code. Can someone enlighten me?

Pooja Lalan on 30 Mar 2020

If the output x*y is not assigned to any variable, MATLAB assigns it to the variable ans by default. In this solution, z has been replaced with ans in the function definition to return the unassigned output.

Hugo Ormo on 5 Apr 2020

I am confused... this ought to work:
function z = in_prod(x,y)
if size(x,2) == size(y,1)
z = x * y
else
z = "The inner dimensions are " + size(x) + " and " + size(y) + ". Matrix multiplication is not possible"
end

Adrià Fenollosa on 23 Jul 2020

This is dot product, not inner product, as the title suggests. They are not exactly the same.

Cheng Jin on 21 Oct 2020

I personally suggest substituting the title with 'dot product', as the description states.

Sebastian Duda on 27 Nov 2020

What is wrong with this code? It's working on the downloaded version.
[xrow,xcol]=size(x);
[yrow,ycol]=size(y);
if xcol==yrow
z = x*y
else
z='Have you checked the inner dimensions?'
end

霖陈 on 28 Oct 2021

please help me,what is wrong with this code?fail the third test...
function z = in_prod(x,y)
if size(x,2)==size(y,1);
z=x*y
else
z=''Have you checked the inner dimensions'
end
end

Isabella Stellitano on 14 Nov 2021

Thank you

Farooq on 15 Sep 2022

DO NOT use disp when printing the string for z, just use z = "string message". Otherwise even if your code is correct it will not complete the problem.

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Problem 44950. Calculate Inner Product

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