Software error doomed Japanese Hitomi spacecraft

Re:Software error doomed Japanese Hitomi spacecraft by microcolonel on Saturday April 30, 2016 @11:52PM (#11604786)

I have seen analyses of ECM software; and I think they could benefit greatly from a new language.

The priority seems to be reliable real-time computation, and the solution is to calculate everything as a continuous function. Anything that would be a branch is instead a binary mix of the conditions, triggered with a threshold function.

I can think of many ways of structuring programs which are spaghettiish in C, but would yield the desired results in an automotive ECM.

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Re:Software error doomed Japanese Hitomi spacecraft by woodman on Sunday May 01, 2016 @01:59AM (#11605062)

I've tackled some problems that would have ideally, from a performance perspective, been implemented with very deeply nested if()'s. I've found a truth table like layout of bool evaluations to be a nice compromise between maintainability and performance:

  void doit(const tststructptr* in) {
    assert(in);  /* Because we test our code, for safety */
    const tststructptr t = *in;
    if      ( t.t1 &&  t.t2 &&  t.t3) { f1(); }
    else if ( t.t1 && !t.t2 &&  t.t3) { f2(); }
    else if ( t.t1 &&  t.t2 && !t.t3) { f3(); }
    else         /* TODO: Fix, this should never happen */
      releasenerveagent(SLEEPINGQUARTERS);
  }

A long sequence of ternary operators allow for a prettier layout, but is more error prone.

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