micnd90 [he/him,any]

  • 2 Posts
  • 26 Comments
Joined 4 years ago
cake
Cake day: August 17th, 2020

help-circle

  • When you say the first element of a matrix, first implies one and not zero. This is how linear algebra was invented (on paper, by a human mathematician), taught, and passed down to fellow humans.

    Starting indexes at zero stem from the lineage of C programming and binary nature of computer. For example,

    Computer memory addresses have 2^N cells addressed by N bits. Now if we start counting at 1, 2^N cells would need N+1 address lines. The extra-bit is needed to access exactly 1 address. (1000 in the above case.). Another way to solve it would be to leave the last address inaccessible, and use N address lines.

    This is why, math and physics people who learn linear algebra and matrix calculus learn to index at 1 (on a piece of paper) while computer science programmers index at 0.


  • MATLAB is for matrix calcs. Matrix indices start at 1, fight me. Given a matrix X of m x n size, you write

    Matlab has many issues, amongst other accessibility (which can be remedied by piracy), closed-software, but as a program designed to do computational matrix manipulation, starting at index 1 is literally correct. This is how you learn matrix indices in intro linear algebra. How is it make sense then you use a software to assist computation and start indexing at 0, while you write the equations and indices on a piece of paper you start at 1. CS majors go home.














  • https://trove.nla.gov.au/newspaper/article/116385390

    HOBART; An official sighting of the Tasmanian tiger, feared extinct for 48 years, was reported yesterday by the State National Parks and Wildlife Service. The tiger was seen 18 months ago by a ranger in forest country in the northwest of the State, according to the service’s chief wildlife officer, Mr Rod Pierce. Mr Pierce said the ranger had been "parked in his car at night doing some other work when he saw it in his spotlight. “It wasn’t a fleeting glimpse - he had long enough to have a good look at the animal.” Mr Pierce said it was one of a number of good sightings of the tiger over the past few years, but it was the only one by a ranger.

    Mr Pierce said the service would not disclose the name of the ranger who made the sighting, nor would it specify the area where it was made. “The tiger must have as much protection as possible.” he said. “We don’t want all sorts of people going out and looking for it.” Rangers have searched along creek banks and through muddy areas looking for footprints. If its general location becomes known, rangers will set up infra-red cameras in the hope of capturing it on film. But Mr Pierce said the search had so far been fruitless and no tracks had been found. “The project will run until the end of summer, and then it will be reviewed,” he said.