Hi, I wanted to display a 6*1 matrix but i only get it's last 5 elements (i.e. the first element doesn't appaear..)
Here's the Simulink blocks and the input variable in Matlab:
MATLAB: Input has is 6*1 matrix but simulink displays only 5*1
MATLABsimulink
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Have you even considered looking at the documentation? It really helps answering your question.
Looking at the documentation, I could find how supplying a vector as the second argument would work, but I get a warning. "repmat(A,M,N) where M or N is a row vector will return an error in a future release. Use repmat(A,[M,N]) instead." This hints at what is happening: it concatenates all inputs into 1 vector.
The first argument is the scalar/vector/matrix that you want to replicate. Then you have 3 options:
- using 1 value, which will result in that many replications in the first two dimensions (rows and cols)
- using 1 vector, which specifies the number of replications in each dimension (e.g. [1 1 3] will replicate a value/vector/matrix into the 3rd dimension, useful for going from greyscale to RGB images)
- splitting the vector over separate arguments
Knowing this it is obvious why your results are what they are. The first replicates a 1x9 vector (1:9) 6 times in the first dimensions (the rows), so you get a 6x9. The second replicates a scalar (so 1x1), using [1:9,1] as the repetition scheme, so the result is a 1x2x3x4x5x6x7x8x9x1 matrix, which is an 9-dimensional matrix (as any trailing x1 can be ignored).
Matlab uses two different functions for these computations, the exponentiation function for 10^61 and the decimal-to-binary conversion function for 1e61. The two can easily arrive at a slightly different answer due to differences in rounding in the respective functions, since in general the two functions have to deal with different types of numbers. This should not be surprising to anyone using digital computers, since rounding errors are an ever-present element in the great majority of computations.
On my own computer the two quantities you mention actually produce identical results. However if I change to 1e64 and 10^64, the results differ by a single bit out of the 53 bits of their respective significands. Why should such a minuscule difference matter? In any case it is impossible to represent either of these quantities exactly as a binary floating point number.
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