How to express inner product of two vectors in Stateflow action language?

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Wilfred
Wilfred 2011-11-11
I want to compute the inner product y of two vectors u and v (same size, both based on input from Simulink) in Stateflow action language. I have tried
x=ml.transpose(u)
y=ml.(x*v)
but during compilation this results in a coder error "Cannot reshape Local Data 'x' (#...) ([...]) to Local Data 'y' (#...) (scalar) for operator =. Please refer to object (#...)." Apparently, the "ml." notation only works with functions, not with operators such as '*'. Would there be a way to write a product as a function - something like y=ml.product(x,v)?
An alternative might be
x=ml.transpose(u)
y=ml('x*v')
but this requires x and v to be defined in the Matlab workspace, which would mean I have to export them first. This seems to be a rather laborious solution.
Any ideas?
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Wilfred
Wilfred 2011-11-14
I should have mentioned that both u and v are composed of integers. However, it seems that solutions are not available in that case, let's assume that u and v are composed of real numbers, as integers can of course also be converted to real numbers.

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采纳的回答

Kaustubha Govind
Kaustubha Govind 2011-11-11
Try the function times for inner product of two vectors.
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Wilfred
Wilfred 2011-11-14
This was not exactly what I was looking for, but it helped me solve my problem. The function "times" multiplies input arrays element by element and puts these in a vector the same size as the input vectors (with no need for transposing one of them as I initially tried). What I wanted was a scalar equal to the sum of the element-by-element multiplications, which can of course be computed from it:
y=ml.sum(ml.times(u,v))

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更多回答（1 个）

Walter Roberson
Walter Roberson 2011-11-11
The MATLAB * operator has the formal name mtimes
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Wilfred
Wilfred 2011-11-14
Thanks, this works too, if put this way:
y=ml.mtimes(ml.transpose(u),v)
Here, the order of listing the arguments is important.

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