Re: [eigen] Comma initializing a very big matrix

[Christoph Hertzberg <chtz@xxxxxxxxxxxxx>]

On 2024-04-05 01:01, Ian Bell wrote:
> Is there a way to (in order of niceness):
> 1. Get the comma init to work

Using the comma-initializer results in a call-graph like:

    operator,(operator,(...,
        operator,(operator<<(MatrixXd,double),
        ...), double), double)

With a 45*45 call-depth this may stress your compiler more than it is 
capable. I would use the comma-initializer only if you need C++03 
compatibility or to compose larger matrices from (a few!) sub-matrices.

> 2. Do a less-annoying workaround

I suggest using much more readable initializer lists:

    const Eigen::MatrixXd kernel_1{
        {0.0, 0.01, 0.02, ..., 0.44},
        {1.0, 1.01 ,1.02, ..., 1.44},
        ...
    };


> 3. At least crash with some sort of useful message

I guess that is a compiler issue. We can't do much from Eigen's side.

Christoph


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