MATLAB wishlist

[EranOfek]

Speed performances

The following suggestions are required in order to improve MATLAB performences:

Binary operators with results stored in the input

When MATLAB performs binary operations (e.g., A+B), it always keep the original inputs and allocate memory for the output. However, BLAS and LINPACK write the result in the input. Therefore, a version of selected binary operators that stores the output in the input variable without allocating memory may be useful in some cases and save run time.

Example:
I suggest a new package 'overinput':
A = overinput.plus(A,B);
A = overinput.times(A,B);
etc.

__ This is already implelemted in MATLAB__

non-complex output functions

Many matlab functions that are defined in the complex plane may return a complex output:
For some applications, I prefer that the output will be real or NaN if imaginary.
I suggest a new package named 'nonimaginary' that will include such functions

For example:
nonimaginary.asin(-2) will return NaN

Additional functions in this package:
asin, acos, ..., log, log10,...

sincos function

A sincos function that return both the sin and cos of a number maybe useful (e.g., using the C builtin sincos function)

operations with flags

Operations on subarray selected by logicals (instead of indices) are not efficient - e.g.,
B = FUN(A(A>1)) is relatively expensive.
I guess this is related to memory allocation, but I guess you can expedite such operations.

Another related operation that can be expedited:
F = A>1
A(F) = FUN(A(F))

filter2 on 3-D arrays

It will be nice to have a function similar to filter2 (i.e., C=filter2(B,X,'same')) in which the filter (B) is a cube
and the output C is a cube in which each layer of B (e.g., B(:,:,i)) is cross-correlated with X).
I guess that a good design of such function will make it much faster than calling filter2 in a loop.

count values

A function that counts the number of appearances of some value in an array like sum(A>1) or sum(~isnan(A)), but more efficiently.

[EranOfek]

The arguments block

The arguments block is very useful, but it has one problem. The metadata on the arguments is not visible.
For example, the user (within some function) can not tell if the variable value defined in the arguments block is originating from the caller function, or the default in the arguments block, and with which arguments the function was called.

See also:
https://www.mathworks.com/matlabcentral/answers/508533-can-i-get-information-of-used-method-arguments-validation-by-meta-class

[agioffe]

Would be nice to build a tool capable of finding a "most suitable" stellar spectrum from the AstroPack's library for a given pair of T_eff and log(g) values.