It will probably depend on how big b is (and what it is – your code doesn’t run as you wrote it above). If your replicated vector makes too large a matrix, you might look into whether a sparse diagonal matrix will work better for you. And perhaps also bsxfun, but I can’t think of how that would work exactly, esp. since I don’t have MATLAB nearby.

–loren

myMatrix = magic(3)
myVector = [1 2 3]'
repVector = repmat(b,1,3)
myOutput = myMatrix.*repVector

You say “the data comes out in various columns and not awlays the number of ones I specified with %f”. That’s because the fprintf command is vectorized and repeats the format if the data you present are larger. You need to make sure the format is an exact multiple of the number of elements/row (and that that is a fixed number) for your data.

–Loren

I have some data in a 3D matrix. Specifically, I have 100 layers of a [90 column by 100 row] rectangle. When I click inside the Array Editor, it always “wraps” the columns onto subsequent rows instead of preseting the data in neat grids which I could then paste into Excel. Also, when I try to use the code: fprintf(fid,’%7.4f %7.4f %7.4f %7.4f\n’,PortWts), the data comes out in various columns and not awlays the number of ones I specified with %f. To sum up, what is the best way to export a complex matrix or array in order to preserve the neatness of grids so that I don’t have to copy and paste and fix them in EXCEL? Even the ‘diary’ function exports the data in a wrapped column format. I basically want the data to appear as nicely as it does in the Array Editor for a simple 2-D matrix or rectangle, but for subsequent layers of more complex data etc. I use the student version by the way. Please advise.

Tony

And BTW, the fact that it would trivialize part of the operation — the transpose but not the conjugation — is harmless. (You could make an even stronger case for the uselessness of dot-plus. But it is harmless as an operator in its own right, and its semantics are consistent with what dot does to the other common operators. So putting it in the language is probably a GOOD design choice, not merely a harmless one.)

Perhaps conjugate-transpose should not have been given the simple apostrophe notation. But once it was, the meaning of .’ was really not open for negotiation. The adopted usage introduced a completely avoidable inconsistency in the language, and was thus a mistake in language design.

FWIW, this is (IMO) not the worst of MATLAB’s inconsistencies — and yet MATLAB is far, far better than most common languages in its design.

About “.’”: I think what Joel says does make sense. This “like the operator, but applied element-by-element” is how many people (including me) see the period operator. So if ‘ is conjugate transpose, .’ would conjugate the elements. Perhaps using ‘ for transpose only and ” for conjugate transpose would’ve been clearer, but that’s a question of personal taste IMO.

I understand what you are saying about dot meaning element-wise for the other operations, but what does element-wise transpose mean? Transposing a scalar is the same scalar. I don’t see why .’ should then mean conjugate each element; that’s what the function conj does. So it’s not clear to me that defining .’ the way you suggest would have been useful and not confusing.

–Loren

It is one thing to trip up beginners who have been “damaged” [Dijkstra's word] by other languages and therefore do not use the Matlab language appropriately. It is quite another to introduce an INTERNAL inconsistency into that language.

Another problem I see is just the opposite … when MATLAB’s expressiveness is *not* used, resulting in ugly code. Some beginners try to write MATLAB as if it’s C/Fortran/Java. They write ugly and lengthy loops when a simple, elegant, and easy-to-read one-line vector statement could be used instead.

My favorite abuse of MATLAB, however, is using x=inv(A)*b instead of x=A\b. I would love it if MATLAB were to generate a warning message whenever it saw “inv(A)*b” …