How to initialize an immutable array

[FG]

On 2013-03-01 22:05, Sparsh Mittal wrote:
> On Friday, 1 March 2013 at 20:28:19 UTC, FG wrote:
>> I suppose this:
>>
>> immutable long DIM = 1024L*1024L *128L;
>> immutable(double)[] signal = new double[DIM+1];
>> static this() {
>>     for (long i=0L; i< DIM+1; i++) {
>>         signal[i] = (i+DIM)%7 + (i+DIM+1)%5;
>>     }
>> }
>> void main()
>> { ... }
>
> Thanks. This gives an error, which I don't know how to resolve:
>
> Error: cannot evaluate new double[](134217729LU) at compile time
>
> Can you please tell.


Oh, sorry. Was typing without thinking. :)
Here's a working sample (with long changed to uint):


import std.stdio, std.datetime, std.parallelism, std.range;
double my_abs(double n) { return n > 0 ? n : -n; }
immutable uint DIM = 1024 * 1024 * 128;
immutable(double)[] signal;

static this() {
     auto temp = new double[DIM+1];
     for (uint i = 0; i < DIM + 1; i++)
         temp[i] = (i + DIM) % 7 + (i + DIM + 1) % 5;
     signal = cast(immutable)temp;
}

void main()
{
     double temp;
     double sample[2] = [4.1,7.2];
     StopWatch sw;
     sw.start();
     for (uint i = 0; i < DIM; i++)
     {
         temp = my_abs(sample[0]-signal[i])
             + my_abs(sample[1]-signal[i+1]);
     }
     sw.stop();
     writeln(" Total time: ", (sw.peek().msecs/1000), "[sec]");
}